/* stbi-0.92 - public domain JPEG/PNG reader - http://nothings.org/stb_image.c when you control the images you're loading TODO: stbi_info_* history: 0.92 read 4,8,16,24,32-bit BMP files of several formats 0.91 output 24-bit Windows 3.0 BMP files 0.90 fix a few more warnings; bump version number to approach 1.0 0.61 bugfixes due to Marc LeBlanc, Christopher Lloyd 0.60 fix compiling as c++ 0.59 fix warnings: merge Dave Moore's -Wall fixes 0.58 fix bug: zlib uncompressed mode len/nlen was wrong endian 0.57 fix bug: jpg last huffman symbol before marker was >9 bits but less than 16 available 0.56 fix bug: zlib uncompressed mode len vs. nlen 0.55 fix bug: restart_interval not initialized to 0 0.54 allow NULL for 'int *comp' 0.53 fix bug in png 3->4; speedup png decoding 0.52 png handles req_comp=3,4 directly; minor cleanup; jpeg comments 0.51 obey req_comp requests, 1-component jpegs return as 1-component, on 'test' only check type, not whether we support this variant */ //// begin header file //////////////////////////////////////////////////// // // Limitations: // - no progressive/interlaced support (jpeg, png) // - 8-bit samples only (jpeg, png) // - not threadsafe // - channel subsampling of at most 2 in each dimension (jpeg) // - no delayed line count (jpeg) -- image height must be in header // - unsophisticated error handling // // Basic usage: // int x,y,n; // unsigned char *data = stbi_load(filename, &x, &y, &n, 0); // // ... process data if not NULL ... // // ... x = width, y = height, n = # 8-bit components per pixel ... // // ... replace '0' with '1'..'4' to force that many components per pixel // stbi_image_free(data) // // Standard parameters: // int *x -- outputs image width in pixels // int *y -- outputs image height in pixels // int *comp -- outputs # of image components in image file // int req_comp -- if non-zero, # of image components requested in result // // The return value from an image loader is an 'unsigned char *' which points // to the pixel data. The pixel data consists of *y scanlines of *x pixels, // with each pixel consisting of N interleaved 8-bit components; the first // pixel pointed to is top-left-most in the image. There is no padding between // image scanlines or between pixels, regardless of format. The number of // components N is 'req_comp' if req_comp is non-zero, or *comp otherwise. // If req_comp is non-zero, *comp has the number of components that _would_ // have been output otherwise. E.g. if you set req_comp to 4, you will always // get RGBA output, but you can check *comp to easily see if it's opaque. // // An output image with N components has the following components interleaved // in this order in each pixel: // // N=#comp components // 1 grey // 2 grey, alpha // 3 red, green, blue // 4 red, green, blue, alpha // // If image loading fails for any reason, the return value will be NULL, // and *x, *y, *comp will be unchanged. The function stbi_failure_reason() // can be queried for an extremely brief, end-user unfriendly explanation // of why the load failed. Define STB_IMAGE_NO_FAILURE_REASON to avoid // compiling these strings at all. // // Paletted PNG images are automatically depalettized. #include enum { STBI_default = 0, // only used for req_comp STBI_grey = 1, STBI_grey_alpha = 2, STBI_rgb = 3, STBI_rgb_alpha = 4, }; typedef unsigned char stbi_uc; #ifdef __cplusplus extern "C" { #endif // WRITING API #ifndef STBI_NO_WRITE // write a BMP/TGA file given tightly packed 'comp' channels (no padding, nor bmp-stride-padding) // (you must include the appropriate extension in the filename). // returns TRUE on success, FALSE if couldn't open file, error writing file extern int stbi_write_bmp (char *filename, int x, int y, int comp, void *data); extern int stbi_write_tga (char *filename, int x, int y, int comp, void *data); #endif // PRIMARY API - works on images of any type // load image by filename, open file, or memory buffer extern stbi_uc *stbi_load (char *filename, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_load_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp); // for stbi_load_from_file, file pointer is left pointing immediately after image // get a VERY brief reason for failure extern char *stbi_failure_reason (void); // free the loaded image -- this is just free() extern void stbi_image_free (stbi_uc *retval_from_stbi_load); // get image dimensions & components without fully decoding extern int stbi_info (char *filename, int *x, int *y, int *comp); extern int stbi_info_from_file (char *filename, int *x, int *y, int *comp); extern int stbi_info_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp); // ZLIB client - used by PNG, available for other purposes extern char *stbi_zlib_decode_malloc_guesssize(int initial_size, int *outlen); extern char *stbi_zlib_decode_malloc(char *buffer, int len, int *outlen); extern int stbi_zlib_decode_buffer(char *obuffer, int olen, char *ibuffer, int ilen); // TYPE-SPECIFIC ACCESS // is it a jpeg? extern int stbi_jpeg_test_file (FILE *f); extern int stbi_jpeg_test_memory (stbi_uc *buffer, int len); extern stbi_uc *stbi_jpeg_load (char *filename, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_jpeg_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_jpeg_load_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp); extern int stbi_jpeg_info (char *filename, int *x, int *y, int *comp); extern int stbi_jpeg_info_from_file (FILE *f, int *x, int *y, int *comp); extern int stbi_jpeg_info_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp); extern int stbi_jpeg_dc_only; // only decode DC component // is it a png? extern int stbi_png_test_file (FILE *f); extern int stbi_png_test_memory (stbi_uc *buffer, int len); extern stbi_uc *stbi_png_load (char *filename, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_png_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_png_load_from_memory (stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp); extern int stbi_png_info (char *filename, int *x, int *y, int *comp); extern int stbi_png_info_from_file (FILE *f, int *x, int *y, int *comp); extern int stbi_png_info_from_memory (stbi_uc *buffer, int len, int *x, int *y, int *comp); // is it a bmp? extern int stbi_bmp_test_file (FILE *f); extern int stbi_bmp_test_memory (stbi_uc *buffer, int len); extern stbi_uc *stbi_bmp_load (char *filename, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_bmp_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp); extern stbi_uc *stbi_bmp_load_from_memory (stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp); #ifdef __cplusplus } #endif // // //// end header file ///////////////////////////////////////////////////// #include #include #include #include #include #ifndef _MSC_VER #define __forceinline #endif // implementation: typedef unsigned char uint8; typedef unsigned short uint16; typedef signed short int16; typedef unsigned int uint32; typedef signed int int32; typedef unsigned int uint; // should produce compiler error if size is wrong typedef unsigned char validate_uint32[sizeof(uint32)==4]; ////////////////////////////////////////////////////////////////////////////// // // Generic API that works on all image types // static char *failure_reason; char *stbi_failure_reason(void) { return failure_reason; } static int e(char *str) { failure_reason = str; return 0; } #ifdef STB_IMAGE_NO_FAILURE_STRINGS #define e(x) 0 #endif #define ep(x) (e(x),NULL) void stbi_image_free(unsigned char *retval_from_stbi_load) { free(retval_from_stbi_load); } unsigned char *stbi_load(char *filename, int *x, int *y, int *comp, int req_comp) { FILE *f = fopen(filename, "rb"); unsigned char *result; if (!f) return ep("can't fopen"); result = stbi_load_from_file(f,x,y,comp,req_comp); fclose(f); return result; } unsigned char *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp) { if (stbi_jpeg_test_file(f)) return stbi_jpeg_load_from_file(f,x,y,comp,req_comp); if (stbi_png_test_file(f)) return stbi_png_load_from_file(f,x,y,comp,req_comp); if (stbi_bmp_test_file(f)) return stbi_bmp_load_from_file(f,x,y,comp,req_comp); return ep("unknown image type"); } unsigned char *stbi_load_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp) { if (stbi_jpeg_test_memory(buffer,len)) return stbi_jpeg_load_from_memory(buffer,len,x,y,comp,req_comp); if (stbi_png_test_memory(buffer,len)) return stbi_png_load_from_memory(buffer,len,x,y,comp,req_comp); if (stbi_bmp_test_memory(buffer,len)) return stbi_bmp_load_from_memory(buffer,len,x,y,comp,req_comp); return ep("unknown image type"); } // @TODO: get image dimensions & components without fully decoding extern int stbi_info (char *filename, int *x, int *y, int *comp); extern int stbi_info_from_file (char *filename, int *x, int *y, int *comp); extern int stbi_info_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp); ////////////////////////////////////////////////////////////////////////////// // // Common code used by all image loaders // // image width, height, # components static uint32 img_x, img_y; static int img_n, img_out_n; enum { SCAN_load=0, SCAN_type, SCAN_header, }; // An API for reading either from memory or file. // It fits on a single screen. No abstract base classes needed. static FILE *img_file; static uint8 *img_buffer, *img_buffer_end; static void start_file(FILE *f) { img_file = f; } static void start_mem(uint8 *buffer, int len) { img_file = NULL; img_buffer = buffer; img_buffer_end = buffer+len; } static int get8(void) { if (img_file) { int c = fgetc(img_file); return c == EOF ? 0 : c; } else { if (img_buffer < img_buffer_end) return *img_buffer++; return 0; } } static uint8 get8u(void) { return (uint8) get8(); } static void skip(int n) { if (img_file) fseek(img_file, n, SEEK_CUR); else img_buffer += n; } static int get16(void) { int z = get8(); return (z << 8) + get8(); } static uint32 get32(void) { uint32 z = get16(); return (z << 16) + get16(); } static int get16le(void) { int z = get8(); return z + (get8() << 8); } static uint32 get32le(void) { uint32 z = get16le(); return z + (get16le() << 16); } static void getn(stbi_uc *buffer, int n) { if (img_file) fread(buffer, 1, n, img_file); else { memcpy(buffer, img_buffer, n); img_buffer += n; } } ////////////////////////////////////////////////////////////////////////////// // // generic converter from built-in img_n to req_comp // individual types do this automatically as much as possible (e.g. jpeg // does all cases internally since it needs to colorspace convert anyway, // and it never has alpha, so very few cases ). png can automatically // interleave an alpha=255 channel, but falls back to this for other cases // // assume data buffer is malloced, so malloc a new one and free that one // only failure mode is malloc failing static uint8 compute_y(int r, int g, int b) { return (uint8) (((r*77) + (g*150) + (29*b)) >> 8); } static unsigned char *convert_format(unsigned char *data, int img_n, int req_comp) { uint i,j; unsigned char *good; if (req_comp == img_n) return data; assert(req_comp >= 1 && req_comp <= 4); good = (unsigned char *) malloc(req_comp * img_x * img_y); if (good == NULL) { free(data); return ep("outofmem"); } for (j=0; j < img_y; ++j) { unsigned char *src = data + j * img_x * img_n ; unsigned char *dest = good + j * img_x * req_comp; #define COMBO(a,b) ((a)*8+(b)) #define CASE(a,b) case COMBO(a,b): for(i=0; i < img_x; ++i, src += a, dest += b) // convert source image with img_n components to one with req_comp components switch(COMBO(img_n, req_comp)) { CASE(1,2) dest[0]=src[0], dest[1]=255; break; CASE(1,3) dest[0]=dest[1]=dest[2]=src[0]; break; CASE(1,4) dest[0]=dest[1]=dest[2]=src[0], dest[3]=255; break; CASE(2,1) dest[0]=src[0]; break; CASE(2,3) dest[0]=dest[1]=dest[2]=src[0]; break; CASE(2,4) dest[0]=dest[1]=dest[2]=src[0], dest[3]=src[1]; break; CASE(3,4) dest[0]=src[0],dest[1]=src[1],dest[2]=src[2],dest[3]=255; break; CASE(3,1) dest[0]=compute_y(src[0],src[1],src[2]); break; CASE(3,2) dest[0]=compute_y(src[0],src[1],src[2]), dest[1] = 255; break; CASE(4,1) dest[0]=compute_y(src[0],src[1],src[2]); break; CASE(4,2) dest[0]=compute_y(src[0],src[1],src[2]), dest[1] = src[3]; break; CASE(4,3) dest[0]=src[0],dest[1]=src[1],dest[2]=src[2]; break; default: assert(0); } #undef CASE } free(data); img_out_n = req_comp; return good; } ////////////////////////////////////////////////////////////////////////////// // // "baseline" JPEG/JFIF decoder (not actually fully baseline implementation) // // simple implementation // - channel subsampling of at most 2 in each dimension // - doesn't support delayed output of y-dimension // - simple interface (only one output format: 8-bit interleaved RGB) // - doesn't try to recover corrupt jpegs // - doesn't allow partial loading, loading multiple at once // - still fast on x86 (copying globals into locals doesn't help x86) // - allocates lots of intermediate memory (full size of all components) // - non-interleaved case requires this anyway // - allows good upsampling (see next) // high-quality // - upsampled channels are bilinearly interpolated, even across blocks // - quality integer IDCT derived from IJG's 'slow' // performance // - fast huffman; reasonable integer IDCT // - uses a lot of intermediate memory, could cache poorly // - load http://nothings.org/remote/anemones.jpg 3 times on 2.8Ghz P4 // stb_jpeg: 1.34 seconds (MSVC6, default release build) // stb_jpeg: 1.06 seconds (MSVC6, processor = Pentium Pro) // IJL11.dll: 1.08 seconds (compiled by intel) // IJG 1998: 0.98 seconds (MSVC6, makefile provided by IJG) // IJG 1998: 0.95 seconds (MSVC6, makefile + proc=PPro) int stbi_jpeg_dc_only; // huffman decoding acceleration #define FAST_BITS 9 // larger handles more cases; smaller stomps less cache typedef struct { uint8 fast[1 << FAST_BITS]; // weirdly, repacking this into AoS is a 10% speed loss, instead of a win uint16 code[256]; uint8 values[256]; uint8 size[257]; unsigned int maxcode[18]; int delta[17]; // old 'firstsymbol' - old 'firstcode' } huffman; static huffman huff_dc[4]; // baseline is 2 tables, extended is 4 static huffman huff_ac[4]; static uint8 dequant[4][64]; static int build_huffman(huffman *h, int *count) { int i,j,k=0,code; // build size list for each symbol (from JPEG spec) for (i=0; i < 16; ++i) for (j=0; j < count[i]; ++j) h->size[k++] = (uint8) (i+1); h->size[k] = 0; // compute actual symbols (from jpeg spec) code = 0; k = 0; for(j=1; j <= 16; ++j) { // compute delta to add to code to compute symbol id h->delta[j] = k - code; if (h->size[k] == j) { while (h->size[k] == j) h->code[k++] = (uint16) (code++); if (code-1 >= (1 << j)) return e("bad code lengths"); } // compute largest code + 1 for this size, preshifted as needed later h->maxcode[j] = code << (16-j); code <<= 1; } h->maxcode[j] = 0xffffffff; // build non-spec acceleration table; 255 is flag for not-accelerated memset(h->fast, 255, 1 << FAST_BITS); for (i=0; i < k; ++i) { int s = h->size[i]; if (s <= FAST_BITS) { int c = h->code[i] << (FAST_BITS-s); int m = 1 << (FAST_BITS-s); for (j=0; j < m; ++j) { h->fast[c+j] = (uint8) i; } } } return 1; } // sizes for components, interleaved MCUs static int img_h_max, img_v_max; static int img_mcu_x, img_mcu_y; static int img_mcu_w, img_mcu_h; // definition of jpeg image component static struct { int id; int h,v; int tq; int hd,ha; int dc_pred; int x,y,w2,h2; uint8 *data; } img_comp[4]; static unsigned long code_buffer; // jpeg entropy-coded buffer static int code_bits; // number of valid bits static unsigned char marker; // marker seen while filling entropy buffer static int nomore; // flag if we saw a marker so must stop static void grow_buffer_unsafe(void) { do { int b = nomore ? 0 : get8(); if (b == 0xff) { int c = get8(); if (c != 0) { marker = (unsigned char) c; nomore = 1; return; } } code_buffer = (code_buffer << 8) | b; code_bits += 8; } while (code_bits <= 24); } // (1 << n) - 1 static unsigned long bmask[17]={0,1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535}; // decode a jpeg huffman value from the bitstream __forceinline static int decode(huffman *h) { unsigned int temp; int c,k; if (code_bits < 16) grow_buffer_unsafe(); // look at the top FAST_BITS and determine what symbol ID it is, // if the code is <= FAST_BITS c = (code_buffer >> (code_bits - FAST_BITS)) & ((1 << FAST_BITS)-1); k = h->fast[c]; if (k < 255) { if (h->size[k] > code_bits) return -1; code_bits -= h->size[k]; return h->values[k]; } // naive test is to shift the code_buffer down so k bits are // valid, then test against maxcode. To speed this up, we've // preshifted maxcode left so that it has (16-k) 0s at the // end; in other words, regardless of the number of bits, it // wants to be compared against something shifted to have 16; // that way we don't need to shift inside the loop. if (code_bits < 16) temp = (code_buffer << (16 - code_bits)) & 0xffff; else temp = (code_buffer >> (code_bits - 16)) & 0xffff; for (k=FAST_BITS+1 ; ; ++k) if (temp < h->maxcode[k]) break; if (k == 17) { // error! code not found code_bits -= 16; return -1; } if (k > code_bits) return -1; // convert the huffman code to the symbol id c = ((code_buffer >> (code_bits - k)) & bmask[k]) + h->delta[k]; assert((((code_buffer) >> (code_bits - h->size[c])) & bmask[h->size[c]]) == h->code[c]); // convert the id to a symbol code_bits -= k; return h->values[c]; } // combined JPEG 'receive' and JPEG 'extend', since baseline // always extends everything it receives. __forceinline static int extend_receive(int n) { unsigned int m = 1 << (n-1); unsigned int k; if (code_bits < n) grow_buffer_unsafe(); k = (code_buffer >> (code_bits - n)) & bmask[n]; code_bits -= n; // the following test is probably a random branch that won't // predict well. I tried to table accelerate it but failed. // maybe it's compiling as a conditional move? if (k < m) return (-1 << n) + k + 1; else return k; } // given a value that's at position X in the zigzag stream, // where does it appear in the 8x8 matrix coded as row-major? static uint8 dezigzag[64+15] = { 0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63, // let corrupt input sample past end 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }; // decode one 64-entry block-- static int decode_block(short data[64], huffman *hdc, huffman *hac, int b) { int diff,dc,k; int t = decode(hdc); if (t < 0) return e("bad huffman code"); // 0 all the ac values now so we can do it 32-bits at a time memset(data,0,64*sizeof(data[0])); diff = t ? extend_receive(t) : 0; dc = img_comp[b].dc_pred + diff; img_comp[b].dc_pred = dc; data[0] = (short) dc; // decode AC components, see JPEG spec k = 1; do { int r,s; int rs = decode(hac); if (rs < 0) return e("bad huffman code"); s = rs & 15; r = rs >> 4; if (s == 0) { if (rs != 0xf0) break; // end block k += 16; } else { k += r; // decode into unzigzag'd location data[dezigzag[k++]] = (short) extend_receive(s); } } while (k < 64); return 1; } // take a -128..127 value and clamp it and convert to 0..255 __forceinline static uint8 clamp(int x) { x += 128; // trick to use a single test to catch both cases if ((unsigned int) x > 255) { if (x < 0) return 0; if (x > 255) return 255; } return (uint8) x; } #define f2f(x) (int) (((x) * 4096 + 0.5)) #define fsh(x) ((x) << 12) // derived from jidctint -- DCT_ISLOW #define IDCT_1D(s0,s1,s2,s3,s4,s5,s6,s7) \ int t0,t1,t2,t3,p1,p2,p3,p4,p5,x0,x1,x2,x3; \ p2 = s2; \ p3 = s6; \ p1 = (p2+p3) * f2f(0.5411961f); \ t2 = p1 + p3*f2f(-1.847759065f); \ t3 = p1 + p2*f2f( 0.765366865f); \ p2 = s0; \ p3 = s4; \ t0 = fsh(p2+p3); \ t1 = fsh(p2-p3); \ x0 = t0+t3; \ x3 = t0-t3; \ x1 = t1+t2; \ x2 = t1-t2; \ t0 = s7; \ t1 = s5; \ t2 = s3; \ t3 = s1; \ p3 = t0+t2; \ p4 = t1+t3; \ p1 = t0+t3; \ p2 = t1+t2; \ p5 = (p3+p4)*f2f( 1.175875602f); \ t0 = t0*f2f( 0.298631336f); \ t1 = t1*f2f( 2.053119869f); \ t2 = t2*f2f( 3.072711026f); \ t3 = t3*f2f( 1.501321110f); \ p1 = p5 + p1*f2f(-0.899976223f); \ p2 = p5 + p2*f2f(-2.562915447f); \ p3 = p3*f2f(-1.961570560f); \ p4 = p4*f2f(-0.390180644f); \ t3 += p1+p4; \ t2 += p2+p3; \ t1 += p2+p4; \ t0 += p1+p3; // .344 seconds on 3*anemones.jpg static void idct_block(uint8 *out, int out_stride, short data[64], uint8 *dequantize) { int i,val[64],*v=val; uint8 *o,*dq = dequantize; short *d = data; if (stbi_jpeg_dc_only) { // ok, I don't really know why this is right, but it seems to be: int z = 128 + ((d[0] * dq[0]) >> 3); for (i=0; i < 8; ++i) { out[0] = out[1] = out[2] = out[3] = out[4] = out[5] = out[6] = out[7] = z; out += out_stride; } return; } // columns for (i=0; i < 8; ++i,++d,++dq, ++v) { // if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing if (d[ 8]==0 && d[16]==0 && d[24]==0 && d[32]==0 && d[40]==0 && d[48]==0 && d[56]==0) { // no shortcut 0 seconds // (1|2|3|4|5|6|7)==0 0 seconds // all separate -0.047 seconds // 1 && 2|3 && 4|5 && 6|7: -0.047 seconds int dcterm = d[0] * dq[0] << 2; v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm; } else { IDCT_1D(d[ 0]*dq[ 0],d[ 8]*dq[ 8],d[16]*dq[16],d[24]*dq[24], d[32]*dq[32],d[40]*dq[40],d[48]*dq[48],d[56]*dq[56]) // constants scaled things up by 1<<12; let's bring them back // down, but keep 2 extra bits of precision x0 += 512; x1 += 512; x2 += 512; x3 += 512; v[ 0] = (x0+t3) >> 10; v[56] = (x0-t3) >> 10; v[ 8] = (x1+t2) >> 10; v[48] = (x1-t2) >> 10; v[16] = (x2+t1) >> 10; v[40] = (x2-t1) >> 10; v[24] = (x3+t0) >> 10; v[32] = (x3-t0) >> 10; } } for (i=0, v=val, o=out; i < 8; ++i,v+=8,o+=out_stride) { // no fast case since the first 1D IDCT spread components out IDCT_1D(v[0],v[1],v[2],v[3],v[4],v[5],v[6],v[7]) // constants scaled things up by 1<<12, plus we had 1<<2 from first // loop, plus horizontal and vertical each scale by sqrt(8) so together // we've got an extra 1<<3, so 1<<17 total we need to remove. x0 += 65536; x1 += 65536; x2 += 65536; x3 += 65536; o[0] = clamp((x0+t3) >> 17); o[7] = clamp((x0-t3) >> 17); o[1] = clamp((x1+t2) >> 17); o[6] = clamp((x1-t2) >> 17); o[2] = clamp((x2+t1) >> 17); o[5] = clamp((x2-t1) >> 17); o[3] = clamp((x3+t0) >> 17); o[4] = clamp((x3-t0) >> 17); } } #define MARKER_none 0xff // if there's a pending marker from the entropy stream, return that // otherwise, fetch from the stream and get a marker. if there's no // marker, return 0xff, which is never a valid marker value static uint8 get_marker(void) { uint8 x; if (marker != MARKER_none) { x = marker; marker = MARKER_none; return x; } x = get8u(); if (x != 0xff) return MARKER_none; while (x == 0xff) x = get8u(); return x; } // in each scan, we'll have scan_n components, and the order // of the components is specified by order[] static int scan_n, order[4]; static int restart_interval, todo; #define RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7) // after a restart interval, reset the entropy decoder and // the dc prediction static void reset(void) { code_bits = 0; code_buffer = 0; nomore = 0; img_comp[0].dc_pred = img_comp[1].dc_pred = img_comp[2].dc_pred = 0; marker = MARKER_none; todo = restart_interval ? restart_interval : 0x7fffffff; // no more than 1<<31 MCUs if no restart_interal? that's plenty safe, // since we don't even allow 1<<30 pixels } static int parse_entropy_coded_data(void) { reset(); if (scan_n == 1) { int i,j; short data[64]; int n = order[0]; // non-interleaved data, we just need to process one block at a time, // in trivial scanline order // number of blocks to do just depends on how many actual "pixels" this // component has, independent of interleaved MCU blocking and such int w = (img_comp[n].x+7) >> 3; int h = (img_comp[n].y+7) >> 3; for (j=0; j < h; ++j) { for (i=0; i < w; ++i) { if (!decode_block(data, huff_dc+img_comp[n].hd, huff_ac+img_comp[n].ha, n)) return 0; idct_block(img_comp[n].data+img_comp[n].w2*j*8+i*8, img_comp[n].w2, data, dequant[img_comp[n].tq]); // every data block is an MCU, so countdown the restart interval if (--todo <= 0) { if (code_bits < 24) grow_buffer_unsafe(); // if it's NOT a restart, then just bail, so we get corrupt data // rather than no data if (!RESTART(marker)) return 1; reset(); } } } } else { // interleaved! int i,j,k,x,y; short data[64]; for (j=0; j < img_mcu_y; ++j) { for (i=0; i < img_mcu_x; ++i) { // scan an interleaved mcu... process scan_n components in order for (k=0; k < scan_n; ++k) { int n = order[k]; // scan out an mcu's worth of this component; that's just determined // by the basic H and V specified for the component for (y=0; y < img_comp[n].v; ++y) { for (x=0; x < img_comp[n].h; ++x) { int x2 = (i*img_comp[n].h + x)*8; int y2 = (j*img_comp[n].v + y)*8; if (!decode_block(data, huff_dc+img_comp[n].hd, huff_ac+img_comp[n].ha, n)) return 0; idct_block(img_comp[n].data+img_comp[n].w2*y2+x2, img_comp[n].w2, data, dequant[img_comp[n].tq]); } } } // after all interleaved components, that's an interleaved MCU, // so now count down the restart interval if (--todo <= 0) { if (code_bits < 24) grow_buffer_unsafe(); // if it's NOT a restart, then just bail, so we get corrupt data // rather than no data if (!RESTART(marker)) return 1; reset(); } } } } return 1; } static int process_marker(int m) { int L; switch (m) { case MARKER_none: // no marker found return e("expected marker"); case 0xC2: // SOF - progressive return e("progressive jpeg"); case 0xDD: // DRI - specify restart interval if (get16() != 4) return e("bad DRI len"); restart_interval = get16(); return 1; case 0xDB: // DQT - define quantization table L = get16()-2; while (L > 0) { int z = get8(); int p = z >> 4; int t = z & 15,i; if (p != 0) return e("bad DQT type"); if (t > 3) return e("bad DQT table"); for (i=0; i < 64; ++i) dequant[t][dezigzag[i]] = get8u(); L -= 65; } return L==0; case 0xC4: // DHT - define huffman table L = get16()-2; while (L > 0) { uint8 *v; int sizes[16],i,m=0; int z = get8(); int tc = z >> 4; int th = z & 15; if (tc > 1 || th > 3) return e("bad DHT header"); for (i=0; i < 16; ++i) { sizes[i] = get8(); m += sizes[i]; } L -= 17; if (tc == 0) { if (!build_huffman(huff_dc+th, sizes)) return 0; v = huff_dc[th].values; } else { if (!build_huffman(huff_ac+th, sizes)) return 0; v = huff_ac[th].values; } for (i=0; i < m; ++i) v[i] = get8u(); L -= m; } return L==0; } // check for comment block or APP blocks if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) { skip(get16()-2); return 1; } return 0; } // after we see SOS static int process_scan_header(void) { int i; int Ls = get16(); scan_n = get8(); if (scan_n < 1 || scan_n > 4 || scan_n > (int) img_n) return e("bad SOS component count"); if (Ls != 6+2*scan_n) return e("bad SOS len"); for (i=0; i < scan_n; ++i) { int id = get8(), which; int z = get8(); for (which = 0; which < img_n; ++which) if (img_comp[which].id == id) break; if (which == img_n) return 0; img_comp[which].hd = z >> 4; if (img_comp[which].hd > 3) return e("bad DC huff"); img_comp[which].ha = z & 15; if (img_comp[which].ha > 3) return e("bad AC huff"); order[i] = which; } if (get8() != 0) return e("bad SOS"); get8(); // should be 63, but might be 0 if (get8() != 0) return e("bad SOS"); return 1; } static int process_frame_header(int scan) { int Lf,p,i,z, h_max=1,v_max=1; Lf = get16(); if (Lf < 11) return e("bad SOF len"); // JPEG p = get8(); if (p != 8) return e("only 8-bit"); // JPEG baseline img_y = get16(); if (img_y == 0) return e("no header height"); // Legal, but we don't handle it! img_x = get16(); if (img_x == 0) return e("0 width"); // JPEG requires img_n = get8(); if (img_n != 3 && img_n != 1) return e("bad component count"); // JFIF requires if (Lf != 8+3*img_n) return e("bad SOF len"); for (i=0; i < img_n; ++i) { img_comp[i].id = get8(); if (img_comp[i].id != i+1) return e("bad component ID"); // JFIF requires z = get8(); img_comp[i].h = (z >> 4); if (!img_comp[i].h || img_comp[i].h > 4) return e("bad H"); img_comp[i].v = z & 15; if (!img_comp[i].h || img_comp[i].h > 4) return e("bad V"); img_comp[i].tq = get8(); if (img_comp[i].tq > 3) return e("bad TQ"); } if (scan != SCAN_load) return 1; for (i=0; i < img_n; ++i) { if (img_comp[i].h > h_max) h_max = img_comp[i].h; if (img_comp[i].v > v_max) v_max = img_comp[i].v; } // compute interleaved mcu info img_h_max = h_max; img_v_max = v_max; img_mcu_w = h_max * 8; img_mcu_h = v_max * 8; img_mcu_x = (img_x + img_mcu_w-1) / img_mcu_w; img_mcu_y = (img_y + img_mcu_h-1) / img_mcu_h; for (i=0; i < img_n; ++i) { // number of effective pixels (e.g. for non-interleaved MCU) img_comp[i].x = (img_x * img_comp[i].h + h_max-1) / h_max; img_comp[i].y = (img_y * img_comp[i].v + v_max-1) / v_max; // to simplify generation, we'll allocate enough memory to decode // the bogus oversized data from using interleaved MCUs and their // big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't // discard the extra data until colorspace conversion img_comp[i].w2 = img_mcu_x * img_comp[i].h * 8; img_comp[i].h2 = img_mcu_y * img_comp[i].v * 8; img_comp[i].data = (uint8 *) malloc(img_comp[i].w2 * img_comp[i].h2); } return 1; } // use comparisons since in some cases we handle more than one case (e.g. SOF) #define DNL(x) ((x) == 0xdc) #define SOI(x) ((x) == 0xd8) #define EOI(x) ((x) == 0xd9) #define SOF(x) ((x) == 0xc0 || (x) == 0xc1) #define SOS(x) ((x) == 0xda) static int decode_jpeg_header(int scan) { int m; marker = MARKER_none; // initialize cached marker to empty m = get_marker(); if (!SOI(m)) return e("no SOI"); if (scan == SCAN_type) return 1; m = get_marker(); while (!SOF(m)) { if (!process_marker(m)) return 0; m = get_marker(); } if (!process_frame_header(scan)) return 0; return 1; } static int decode_jpeg_image(void) { int m; restart_interval = 0; if (!decode_jpeg_header(SCAN_load)) return 0; m = get_marker(); while (!EOI(m)) { if (SOS(m)) { if (!process_scan_header()) return 0; if (!parse_entropy_coded_data()) return 0; } else { if (!process_marker(m)) return 0; } m = get_marker(); } return 1; } // static jfif-centered resampling with cross-block smoothing // here by cross-block smoothing what I mean is that the resampling // is bilerp and crosses blocks; I dunno what IJG means #define div4(x) ((uint8) ((x) >> 2)) static void resample_v_2(uint8 *out1, uint8 *input, int w, int h, int s) { // need to generate two samples vertically for every one in input uint8 *above; uint8 *below; uint8 *source; uint8 *out2; int i,j; source = input; out2 = out1+w; for (j=0; j < h; ++j) { above = source; source = input + j*s; below = source + s; if (j == h-1) below = source; for (i=0; i < w; ++i) { int n = source[i]*3; out1[i] = div4(above[i] + n); out2[i] = div4(below[i] + n); } out1 += w*2; out2 += w*2; } } static void resample_h_2(uint8 *out, uint8 *input, int w, int h, int s) { // need to generate two samples horizontally for every one in input int i,j; if (w == 1) { for (j=0; j < h; ++j) out[j*2+0] = out[j*2+1] = input[j*s]; return; } for (j=0; j < h; ++j) { out[0] = input[0]; out[1] = div4(input[0]*3 + input[1]); for (i=1; i < w-1; ++i) { int n = input[i]*3; out[i*2-2] = div4(input[i-1] + n); out[i*2-1] = div4(input[i+1] + n); } out[w*2-2] = div4(input[w-2]*3 + input[w-1]); out[w*2-1] = input[w-1]; out += w*2; input += s; } } // .172 seconds on 3*anemones.jpg static void resample_hv_2(uint8 *out, uint8 *input, int w, int h, int s) { // need to generate 2x2 samples for every one in input int i,j; int os = w*2; // generate edge samples... @TODO lerp them! for (i=0; i < w; ++i) { out[i*2+0] = out[i*2+1] = input[i]; out[i*2+(2*h-1)*os+0] = out[i*2+(2*h-1)*os+1] = input[i+(h-1)*w]; } for (j=0; j < h; ++j) { out[j*os*2+0] = out[j*os*2+os+0] = input[j*w]; out[j*os*2+os-1] = out[j*os*2+os+os-1] = input[j*w+i-1]; } // now generate interior samples; i & j point to top left of input for (j=0; j < h-1; ++j) { uint8 *in1 = input+j*s; uint8 *in2 = in1 + s; uint8 *out1 = out + (j*2+1)*os + 1; uint8 *out2 = out1 + os; for (i=0; i < w-1; ++i) { int p00 = in1[0], p01=in1[1], p10=in2[0], p11=in2[1]; int p00_3 = p00*3, p01_3 = p01*3, p10_3 = p10*3, p11_3 = p11*3; #define div16(x) ((uint8) ((x) >> 4)) out1[0] = div16(p00*9 + p01_3 + p10_3 + p11); out1[1] = div16(p01*9 + p00_3 + p01_3 + p10); out2[0] = div16(p10*9 + p11_3 + p00_3 + p01); out2[1] = div16(p11*9 + p10_3 + p01_3 + p00); out1 += 2; out2 += 2; ++in1; ++in2; } } } #define float2fixed(x) ((int) ((x) * 65536 + 0.5)) // 0.38 seconds on 3*anemones.jpg (0.25 with processor = Pro) // VC6 without processor=Pro is generating multiple LEAs per multiply! static void YCbCr_to_RGB_row(uint8 *out, uint8 *y, uint8 *pcb, uint8 *pcr, int count, int step) { int i; for (i=0; i < count; ++i) { int y_fixed = (y[i] << 16) + 32768; // rounding int r,g,b; int cr = pcr[i] - 128; int cb = pcb[i] - 128; r = y_fixed + cr*float2fixed(1.40200f); g = y_fixed - cr*float2fixed(0.71414f) - cb*float2fixed(0.34414f); b = y_fixed + cb*float2fixed(1.77200f); r >>= 16; g >>= 16; b >>= 16; if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; } if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; } if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; } out[0] = (uint8)r; out[1] = (uint8)g; out[2] = (uint8)b; if (step == 4) out[3] = 255; out += step; } } // clean up the temporary component buffers static void cleanup_jpeg(void) { int i; for (i=0; i < img_n; ++i) { if (img_comp[i].data) { free(img_comp[i].data); img_comp[i].data = NULL; } } } static uint8 *load_jpeg_image(int *out_x, int *out_y, int *comp, int req_comp) { int i, n; // validate req_comp if (req_comp < 0 || req_comp > 4) return ep("bad req_comp"); // load a jpeg image from whichever source if (!decode_jpeg_image()) { cleanup_jpeg(); return NULL; } // determine actual number of components to generate n = req_comp ? req_comp : img_n; // resample components to full size... memory wasteful, but this // lets us bilerp across blocks while upsampling for (i=0; i < img_n; ++i) { // if we're outputting fewer than 3 components, we're grey not RGB; // in that case, don't bother upsampling Cb or Cr if (n < 3 && i) continue; // check if the component scale is less than max; if so it needs upsampling if (img_comp[i].h != img_h_max || img_comp[i].v != img_v_max) { int stride = img_x; // allocate final size; make sure it's big enough for upsampling off // the edges with upsample up to 4x4 (although we only support 2x2 // currently) uint8 *new_data = (uint8 *) malloc((img_x+3)*(img_y+3)); if (img_comp[i].h*2 == img_h_max && img_comp[i].v*2 == img_v_max) { int tx = (img_x+1)>>1; resample_hv_2(new_data, img_comp[i].data, tx,(img_y+1)>>1, img_comp[i].w2); stride = tx*2; } else if (img_comp[i].h == img_h_max && img_comp[i].v*2 == img_v_max) { resample_v_2(new_data, img_comp[i].data, img_x,(img_y+1)>>1, img_comp[i].w2); } else if (img_comp[i].h*2 == img_h_max && img_comp[i].v == img_v_max) { int tx = (img_x+1)>>1; resample_h_2(new_data, img_comp[i].data, tx,img_y, img_comp[i].w2); stride = tx*2; } else { // @TODO resample uncommon sampling pattern with nearest neighbor free(new_data); cleanup_jpeg(); return ep("uncommon H or V"); } img_comp[i].w2 = stride; free(img_comp[i].data); img_comp[i].data = new_data; } } // now convert components to output image { uint32 i,j; uint8 *output = (uint8 *) malloc(n * img_x * img_y + 1); if (n >= 3) { // output STBI_rgb_* for (j=0; j < img_y; ++j) { uint8 *y = img_comp[0].data + j*img_comp[0].w2; uint8 *out = output + n * img_x * j; if (img_n == 3) { uint8 *cb = img_comp[1].data + j*img_comp[1].w2; uint8 *cr = img_comp[2].data + j*img_comp[2].w2; YCbCr_to_RGB_row(out, y, cb, cr, img_x, n); } else { for (i=0; i < img_x; ++i) { out[0] = out[1] = out[2] = y[i]; out[3] = 255; // not used if n == 3 out += n; } } } } else { // output STBI_grey_* for (j=0; j < img_y; ++j) { uint8 *y = img_comp[0].data + j*img_comp[0].w2; uint8 *out = output + n * img_x * j; if (n == 1) for (i=0; i < img_x; ++i) *out++ = *y++; else for (i=0; i < img_x; ++i) *out++ = *y++, *out++ = 255; } } cleanup_jpeg(); *out_x = img_x; *out_y = img_y; if (comp) *comp = img_n; // report original components, not output return output; } } unsigned char *stbi_jpeg_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp) { start_file(f); return load_jpeg_image(x,y,comp,req_comp); } unsigned char *stbi_jpeg_load(char *filename, int *x, int *y, int *comp, int req_comp) { unsigned char *data; FILE *f = fopen(filename, "rb"); if (!f) return NULL; data = stbi_jpeg_load_from_file(f,x,y,comp,req_comp); fclose(f); return data; } unsigned char *stbi_jpeg_load_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp) { start_mem(buffer,len); return load_jpeg_image(x,y,comp,req_comp); } int stbi_jpeg_test_file(FILE *f) { int n,r; n = ftell(f); start_file(f); r = decode_jpeg_header(SCAN_type); fseek(f,n,SEEK_SET); return r; } int stbi_jpeg_test_memory(unsigned char *buffer, int len) { start_mem(buffer,len); return decode_jpeg_header(SCAN_type); } // @TODO: extern int stbi_jpeg_info (char *filename, int *x, int *y, int *comp); extern int stbi_jpeg_info_from_file (FILE *f, int *x, int *y, int *comp); extern int stbi_jpeg_info_from_memory(stbi_uc *buffer, int len, int *x, int *y, int *comp); // public domain zlib decode v0.2 Sean Barrett 2006-11-18 // simple implementation // - all input must be provided in an upfront buffer // - all output is written to a single output buffer (can malloc/realloc) // performance // - fast huffman // fast-way is faster to check than jpeg huffman, but slow way is slower #define ZFAST_BITS 9 // accelerate all cases in default tables #define ZFAST_MASK ((1 << ZFAST_BITS) - 1) // zlib-style huffman encoding // (jpegs packs from left, zlib from right, so can't share code) typedef struct { uint16 fast[1 << ZFAST_BITS]; uint16 firstcode[16]; int maxcode[17]; uint16 firstsymbol[16]; uint8 size[288]; uint16 value[288]; } zhuffman; __forceinline static int bitreverse16(int n) { n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1); n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2); n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4); n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8); return n; } __forceinline static int bit_reverse(int v, int bits) { assert(bits <= 16); // to bit reverse n bits, reverse 16 and shift // e.g. 11 bits, bit reverse and shift away 5 return bitreverse16(v) >> (16-bits); } static int zbuild_huffman(zhuffman *z, uint8 *sizelist, int num) { int i,k=0; int code, next_code[16], sizes[17]; // DEFLATE spec for generating codes memset(sizes, 0, sizeof(sizes)); memset(z->fast, 255, sizeof(z->fast)); for (i=0; i < num; ++i) ++sizes[sizelist[i]]; sizes[0] = 0; for (i=1; i < 16; ++i) assert(sizes[i] <= (1 << i)); code = 0; for (i=1; i < 16; ++i) { next_code[i] = code; z->firstcode[i] = (uint16) code; z->firstsymbol[i] = (uint16) k; code = (code + sizes[i]); if (sizes[i]) if (code-1 >= (1 << i)) return e("bad codelengths"); z->maxcode[i] = code << (16-i); // preshift for inner loop code <<= 1; k += sizes[i]; } z->maxcode[16] = 0x10000; // sentinel for (i=0; i < num; ++i) { int s = sizelist[i]; if (s) { int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s]; z->size[c] = (uint8)s; z->value[c] = (uint16)i; if (s <= ZFAST_BITS) { int k = bit_reverse(next_code[s],s); while (k < (1 << ZFAST_BITS)) { z->fast[k] = (uint16) c; k += (1 << s); } } ++next_code[s]; } } return 1; } // zlib-from-memory implementation for PNG reading // because PNG allows splitting the zlib stream arbitrarily, // and it's annoying structurally to have PNG call ZLIB call PNG, // we require PNG read all the IDATs and combine them into a single // memory buffer static uint8 *zbuffer, *zbuffer_end; __forceinline static int zget8(void) { if (zbuffer >= zbuffer_end) return 0; return *zbuffer++; } //static unsigned long code_buffer; static int num_bits; static void fill_bits(void) { do { assert(code_buffer < (1U << num_bits)); code_buffer |= zget8() << num_bits; num_bits += 8; } while (num_bits <= 24); } __forceinline static unsigned int zreceive(int n) { unsigned int k; if (num_bits < n) fill_bits(); k = code_buffer & ((1 << n) - 1); code_buffer >>= n; num_bits -= n; return k; } __forceinline static int zhuffman_decode(zhuffman *z) { int b,s,k; if (num_bits < 16) fill_bits(); b = z->fast[code_buffer & ZFAST_MASK]; if (b < 0xffff) { s = z->size[b]; code_buffer >>= s; num_bits -= s; return z->value[b]; } // not resolved by fast table, so compute it the slow way // use jpeg approach, which requires MSbits at top k = bit_reverse(code_buffer, 16); for (s=ZFAST_BITS+1; ; ++s) if (k < z->maxcode[s]) break; if (s == 16) return -1; // invalid code! // code size is s, so: b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s]; assert(z->size[b] == s); code_buffer >>= s; num_bits -= s; return z->value[b]; } static char *zout; static char *zout_start; static char *zout_end; static int z_expandable; static int expand(int n) // need to make room for n bytes { char *q; int cur, limit; if (!z_expandable) return e("output buffer limit"); cur = (int) (zout - zout_start); limit = (int) (zout_end - zout_start); while (cur + n > limit) limit *= 2; q = (char *) realloc(zout_start, limit); if (q == NULL) return e("outofmem"); zout_start = q; zout = q + cur; zout_end = q + limit; return 1; } static zhuffman z_length, z_distance; static int length_base[31] = { 3,4,5,6,7,8,9,10,11,13, 15,17,19,23,27,31,35,43,51,59, 67,83,99,115,131,163,195,227,258,0,0 }; static int length_extra[31]= { 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 }; static int dist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193, 257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0}; static int dist_extra[32] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13}; static int parse_huffman_block(void) { for(;;) { int z = zhuffman_decode(&z_length); if (z < 256) { if (z < 0) return e("bad huffman code"); // error in huffman codes if (zout >= zout_end) if (!expand(1)) return 0; *zout++ = (char) z; } else { uint8 *p; int len,dist; if (z == 256) return 1; z -= 257; len = length_base[z]; if (length_extra[z]) len += zreceive(length_extra[z]); z = zhuffman_decode(&z_distance); if (z < 0) return e("bad huffman code"); dist = dist_base[z]; if (dist_extra[z]) dist += zreceive(dist_extra[z]); if (zout - zout_start < dist) return e("bad dist"); if (zout + len > zout_end) if (!expand(len)) return 0; p = (uint8 *) (zout - dist); while (len--) *zout++ = *p++; } } } static int compute_huffman_codes(void) { static uint8 length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 }; static zhuffman z_codelength; // static just to save stack space uint8 lencodes[286+32+137];//padding for maximum single op uint8 codelength_sizes[19]; int i,n; int hlit = zreceive(5) + 257; int hdist = zreceive(5) + 1; int hclen = zreceive(4) + 4; memset(codelength_sizes, 0, sizeof(codelength_sizes)); for (i=0; i < hclen; ++i) { int s = zreceive(3); codelength_sizes[length_dezigzag[i]] = (uint8) s; } if (!zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0; n = 0; while (n < hlit + hdist) { int c = zhuffman_decode(&z_codelength); assert(c >= 0 && c < 19); if (c < 16) lencodes[n++] = (uint8) c; else if (c == 16) { c = zreceive(2)+3; memset(lencodes+n, lencodes[n-1], c); n += c; } else if (c == 17) { c = zreceive(3)+3; memset(lencodes+n, 0, c); n += c; } else { assert(c == 18); c = zreceive(7)+11; memset(lencodes+n, 0, c); n += c; } } if (n != hlit+hdist) return e("bad codelengths"); if (!zbuild_huffman(&z_length, lencodes, hlit)) return 0; if (!zbuild_huffman(&z_distance, lencodes+hlit, hdist)) return 0; return 1; } static int parse_uncompressed_block(void) { uint8 header[4]; int len,nlen,k; if (num_bits & 7) zreceive(num_bits & 7); // discard // drain the bit-packed data into header k = 0; while (num_bits > 0) { header[k++] = (uint8) (code_buffer & 255); // wtf this warns? code_buffer >>= 8; num_bits -= 8; } assert(num_bits == 0); // now fill header the normal way while (k < 4) header[k++] = (uint8) zget8(); len = header[1] * 256 + header[0]; nlen = header[3] * 256 + header[2]; if (nlen != (len ^ 0xffff)) return e("zlib corrupt"); if (zbuffer + len > zbuffer_end) return e("read past buffer"); if (zout + len > zout_end) if (!expand(len)) return 0; memcpy(zout, zbuffer, len); zbuffer += len; zout += len; return 1; } static int parse_zlib_header(void) { int cmf = zget8(); int cm = cmf & 15; /* int cinfo = cmf >> 4; */ int flg = zget8(); if ((cmf*256+flg) % 31 != 0) return e("bad zlib header"); // zlib spec if (flg & 32) return e("no preset dict"); // preset dictionary not allowed in png if (cm != 8) return e("bad compression"); // DEFLATE required for png // window = 1 << (8 + cinfo)... but who cares, we fully buffer output return 1; } static uint8 default_length[288], default_distance[32]; static void init_defaults(void) { int i; // use <= to match clearly with spec for (i=0; i <= 143; ++i) default_length[i] = 8; for ( ; i <= 255; ++i) default_length[i] = 9; for ( ; i <= 279; ++i) default_length[i] = 7; for ( ; i <= 287; ++i) default_length[i] = 8; for (i=0; i <= 31; ++i) default_distance[i] = 5; } static int parse_zlib(void) { int final, type; if (!parse_zlib_header()) return 0; num_bits = 0; code_buffer = 0; do { final = zreceive(1); type = zreceive(2); if (type == 0) { if (!parse_uncompressed_block()) return 0; } else if (type == 3) { return 0; } else { if (type == 1) { // use fixed code lengths if (!default_length[0]) init_defaults(); if (!zbuild_huffman(&z_length , default_length , 288)) return 0; if (!zbuild_huffman(&z_distance, default_distance, 32)) return 0; } else { if (!compute_huffman_codes()) return 0; } if (!parse_huffman_block()) return 0; } } while (!final); return 1; } static int do_zlib(char *obuf, int olen, int exp) { zout_start = obuf; zout = obuf; zout_end = obuf + olen; z_expandable = exp; return parse_zlib(); } char *stbi_zlib_decode_malloc_guesssize(int initial_size, int *outlen) { char *p = (char *) malloc(initial_size); if (p == NULL) return NULL; if (do_zlib(p, initial_size, 1)) { *outlen = (int) (zout - zout_start); return zout_start; } else { free(zout_start); return NULL; } } char *stbi_zlib_decode_malloc(char *buffer, int len, int *outlen) { zbuffer = (uint8 *) buffer; zbuffer_end = (uint8 *) buffer+len; return stbi_zlib_decode_malloc_guesssize(16384, outlen); } int stbi_zlib_decode_buffer(char *obuffer, int olen, char *ibuffer, int ilen) { zbuffer = (uint8 *) ibuffer; zbuffer_end = (uint8 *) ibuffer + ilen; if (do_zlib(obuffer, olen, 0)) return (int) (zout - zout_start); else return -1; } // public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18 // simple implementation // - only 8-bit samples // - no CRC checking // - allocates lots of intermediate memory // - avoids problem of streaming data between subsystems // - avoids explicit window management // performance // - uses stb_zlib, a PD zlib implementation with fast huffman decoding typedef struct { unsigned long length; unsigned long type; } chunk; #define PNG_TYPE(a,b,c,d) (((a) << 24) + ((b) << 16) + ((c) << 8) + (d)) static chunk get_chunk_header(void) { chunk c; c.length = get32(); c.type = get32(); return c; } static int check_png_header(void) { static uint8 png_sig[8] = { 137,80,78,71,13,10,26,10 }; int i; for (i=0; i < 8; ++i) if (get8() != png_sig[i]) return e("bad png sig"); return 1; } static uint8 *idata, *expanded, *out; enum { F_none=0, F_sub=1, F_up=2, F_avg=3, F_paeth=4, F_avg_first, F_paeth_first, }; static uint8 first_row_filter[5] = { F_none, F_sub, F_none, F_avg_first, F_paeth_first }; static int paeth(int a, int b, int c) { int p = a + b - c; int pa = abs(p-a); int pb = abs(p-b); int pc = abs(p-c); if (pa <= pb && pa <= pc) return a; if (pb <= pc) return b; return c; } // create the png data from post-deflated data static int create_png_image(uint8 *raw, uint32 raw_len, int out_n) { uint32 i,j,stride = img_x*out_n; int k; assert(out_n == img_n || out_n == img_n+1); out = (uint8 *) malloc(img_x * img_y * out_n); if (!out) return e("outofmem"); if (raw_len != (img_n * img_x + 1) * img_y) return e("not enough pixels"); for (j=0; j < img_y; ++j) { uint8 *cur = out + stride*j; uint8 *prior = cur - stride; int filter = *raw++; if (filter > 4) return e("invalid filter"); // if first row, use special filter that doesn't sample previous row if (j == 0) filter = first_row_filter[filter]; // handle first pixel explicitly for (k=0; k < img_n; ++k) { switch(filter) { case F_none : cur[k] = raw[k]; break; case F_sub : cur[k] = raw[k]; break; case F_up : cur[k] = raw[k] + prior[k]; break; case F_avg : cur[k] = raw[k] + (prior[k]>>1); break; case F_paeth : cur[k] = (uint8) (raw[k] + paeth(0,prior[k],0)); break; case F_avg_first : cur[k] = raw[k]; break; case F_paeth_first: cur[k] = raw[k]; break; } } if (img_n != out_n) cur[img_n] = 255; raw += img_n; cur += out_n; prior += out_n; // this is a little gross, so that we don't switch per-pixel or per-component if (img_n == out_n) { #define CASE(f) \ case f: \ for (i=1; i < img_x; ++i, raw+=img_n,cur+=img_n,prior+=img_n) \ for (k=0; k < img_n; ++k) switch(filter) { CASE(F_none) cur[k] = raw[k]; break; CASE(F_sub) cur[k] = raw[k] + cur[k-img_n]; break; CASE(F_up) cur[k] = raw[k] + prior[k]; break; CASE(F_avg) cur[k] = raw[k] + ((prior[k] + cur[k-img_n])>>1); break; CASE(F_paeth) cur[k] = (uint8) (raw[k] + paeth(cur[k-img_n],prior[k],prior[k-img_n])); break; CASE(F_avg_first) cur[k] = raw[k] + (cur[k-img_n] >> 1); break; CASE(F_paeth_first) cur[k] = (uint8) (raw[k] + paeth(cur[k-img_n],0,0)); break; } #undef CASE } else { assert(img_n+1 == out_n); #define CASE(f) \ case f: \ for (i=1; i < img_x; ++i, cur[img_n]=255,raw+=img_n,cur+=out_n,prior+=out_n) \ for (k=0; k < img_n; ++k) switch(filter) { CASE(F_none) cur[k] = raw[k]; break; CASE(F_sub) cur[k] = raw[k] + cur[k-out_n]; break; CASE(F_up) cur[k] = raw[k] + prior[k]; break; CASE(F_avg) cur[k] = raw[k] + ((prior[k] + cur[k-out_n])>>1); break; CASE(F_paeth) cur[k] = (uint8) (raw[k] + paeth(cur[k-out_n],prior[k],prior[k-out_n])); break; CASE(F_avg_first) cur[k] = raw[k] + (cur[k-out_n] >> 1); break; CASE(F_paeth_first) cur[k] = (uint8) (raw[k] + paeth(cur[k-out_n],0,0)); break; } #undef CASE } } return 1; } static int compute_transparency(uint8 tc[3], int out_n) { uint32 i, pixel_count = img_x * img_y; uint8 *p = out; // compute color-based transparency, assuming we've // already got 255 as the alpha value in the output assert(out_n == 2 || out_n == 4); p = out; if (out_n == 2) { for (i=0; i < pixel_count; ++i) { p[1] = (p[0] == tc[0] ? 0 : 255); p += 2; } } else { for (i=0; i < pixel_count; ++i) { if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2]) p[3] = 0; p += 4; } } return 1; } static int expand_palette(uint8 *palette, int len, int pal_img_n) { uint32 i, pixel_count = img_x * img_y; uint8 *p, *temp_out, *orig = out; p = (uint8 *) malloc(pixel_count * pal_img_n); if (p == NULL) return e("outofmem"); // between here and free(out) below, exitting would leak temp_out = p; if (pal_img_n == 3) { for (i=0; i < pixel_count; ++i) { int n = orig[i]*4; p[0] = palette[n ]; p[1] = palette[n+1]; p[2] = palette[n+2]; p += 3; } } else { for (i=0; i < pixel_count; ++i) { int n = orig[i]*4; p[0] = palette[n ]; p[1] = palette[n+1]; p[2] = palette[n+2]; p[3] = palette[n+3]; p += 4; } } free(out); out = temp_out; return 1; } static int parse_png_file(int scan, int req_comp) { uint8 palette[1024], pal_img_n=0; uint8 has_trans=0, tc[3]; uint32 ioff=0, idata_limit=0, i, pal_len=0; int first=1,k; if (!check_png_header()) return e("not png"); if (scan == SCAN_type) return 1; for(;;first=0) { chunk c = get_chunk_header(); if (first && c.type != PNG_TYPE('I','H','D','R')) return e("first not IHDR"); switch (c.type) { case PNG_TYPE('I','H','D','R'): { int depth,color,interlace,comp,filter; if (!first) return e("multiple IHDR"); if (c.length != 13) return e("bad IHDR len"); img_x = get32(); if (img_x > (1 << 24)) return e("too large"); img_y = get32(); if (img_y > (1 << 24)) return e("too large"); depth = get8(); if (depth != 8) return e("8bit only"); color = get8(); if (color > 6) return e("bad ctype"); if (color == 3) pal_img_n = 3; else if (color & 1) return e("bad ctype"); comp = get8(); if (comp) return e("bad comp method"); filter= get8(); if (filter) return e("bad filter method"); interlace = get8(); if (interlace) return e("interlaced"); if (!img_x || !img_y) return e("0-pixel image"); if (!pal_img_n) { img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0); if ((1 << 30) / img_x / img_n < img_y) return e("too large"); if (scan == SCAN_header) return 1; } else { // if paletted, then pal_n is our final components, and // img_n is # components to decompress/filter. img_n = 1; if ((1 << 30) / img_x / 4 < img_y) return e("too large"); // if SCAN_header, have to scan to see if we have a tRNS } break; } case PNG_TYPE('P','L','T','E'): { if (c.length > 256*3) return e("invalid PLTE"); pal_len = c.length / 3; if (pal_len * 3 != c.length) return e("invalid PLTE"); for (i=0; i < pal_len; ++i) { palette[i*4+0] = get8u(); palette[i*4+1] = get8u(); palette[i*4+2] = get8u(); palette[i*4+3] = 255; } break; } case PNG_TYPE('t','R','N','S'): { if (idata) return e("tRNS after IDAT"); if (pal_img_n) { if (scan == SCAN_header) { img_n = 4; return 1; } if (pal_len == 0) return e("tRNS before PLTE"); if (c.length > pal_len) return e("bad tRNS len"); for (i=0; i < c.length; ++i) palette[i*4+3] = get8u(); } else { if (!(img_n & 1)) return e("tRNS with alpha"); if (c.length != (uint32) img_n*2) return e("bad tRNS len"); has_trans = 1; for (k=0; k < img_n; ++k) tc[k] = (uint8) get16(); // non 8-bit images will be larger } break; } case PNG_TYPE('I','D','A','T'): { if (pal_img_n && !pal_len) return e("no PLTE"); if (scan == SCAN_header) { img_n = pal_img_n; return 1; } if (ioff + c.length > idata_limit) { uint8 *p; if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096; while (ioff + c.length > idata_limit) idata_limit *= 2; p = (uint8 *) realloc(idata, idata_limit); if (p == NULL) return e("outofmem"); idata = p; } if (img_file) { if (fread(idata+ioff,1,c.length,img_file) != c.length) return e("outofdata"); } else { memcpy(idata+ioff, img_buffer, c.length); img_buffer += c.length; } ioff += c.length; break; } case PNG_TYPE('I','E','N','D'): { uint32 raw_len; if (scan != SCAN_load) return 1; if (idata == NULL) return e("no IDAT"); expanded = (uint8 *) stbi_zlib_decode_malloc((char *) idata, ioff, (int *) &raw_len); if (expanded == NULL) return 0; // zlib should set error free(idata); idata = NULL; if ((req_comp == img_n+1 && req_comp != 3 && !pal_img_n) || has_trans) img_out_n = img_n+1; else img_out_n = img_n; if (!create_png_image(expanded, raw_len, img_out_n)) return 0; if (has_trans) if (!compute_transparency(tc, img_out_n)) return 0; if (pal_img_n) { // pal_img_n == 3 or 4 img_n = pal_img_n; // record the actual colors we had img_out_n = pal_img_n; if (req_comp >= 3) img_out_n = req_comp; if (!expand_palette(palette, pal_len, img_out_n)) return 0; } free(expanded); expanded = NULL; return 1; } default: // if critical, fail if ((c.type & (1 << 29)) == 0) { #ifndef STB_IMAGE_NO_FAILURE_STRINGS static char invalid_chunk[] = "XXXX chunk not known"; invalid_chunk[0] = (uint8) (c.type >> 24); invalid_chunk[1] = (uint8) (c.type >> 16); invalid_chunk[2] = (uint8) (c.type >> 8); invalid_chunk[3] = (uint8) (c.type >> 0); #endif return e(invalid_chunk); } skip(c.length); break; } // end of chunk, read and skip CRC get8(); get8(); get8(); get8(); } } static unsigned char *do_png(int *x, int *y, int *n, int req_comp) { unsigned char *result=NULL; if (req_comp < 0 || req_comp > 4) return ep("bad req_comp"); if (parse_png_file(SCAN_load, req_comp)) { result = out; out = NULL; if (req_comp && req_comp != img_out_n) { result = convert_format(result, img_out_n, req_comp); if (result == NULL) return result; } *x = img_x; *y = img_y; if (n) *n = img_n; } free(out); out = NULL; free(expanded); expanded = NULL; free(idata); idata = NULL; return result; } unsigned char *stbi_png_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp) { start_file(f); return do_png(x,y,comp,req_comp); } unsigned char *stbi_png_load(char *filename, int *x, int *y, int *comp, int req_comp) { unsigned char *data; FILE *f = fopen(filename, "rb"); if (!f) return NULL; data = stbi_png_load_from_file(f,x,y,comp,req_comp); fclose(f); return data; } unsigned char *stbi_png_load_from_memory(unsigned char *buffer, int len, int *x, int *y, int *comp, int req_comp) { start_mem(buffer,len); return do_png(x,y,comp,req_comp); } int stbi_png_test_file(FILE *f) { int n,r; n = ftell(f); start_file(f); r = parse_png_file(SCAN_type,STBI_default); fseek(f,n,SEEK_SET); return r; } int stbi_png_test_memory(unsigned char *buffer, int len) { start_mem(buffer, len); return parse_png_file(SCAN_type,STBI_default); } // TODO: load header from png extern int stbi_png_info (char *filename, int *x, int *y, int *comp); extern int stbi_png_info_from_file (FILE *f, int *x, int *y, int *comp); extern int stbi_png_info_from_memory (stbi_uc *buffer, int len, int *x, int *y, int *comp); /////////////////////// write image /////////////////////// // Microsoft/Windows BMP image static int bmp_test(void) { int sz; if (get8() != 'B') return 0; if (get8() != 'M') return 0; get32le(); // discard filesize get16le(); // discard reserved get16le(); // discard reserved get32le(); // discard data offset sz = get32le(); if (sz == 12 || sz == 40 || sz == 108) return 1; return 0; } int stbi_bmp_test_file (FILE *f) { int r,n = ftell(f); start_file(f); r = bmp_test(); fseek(f,n,SEEK_SET); return r; } int stbi_bmp_test_memory (stbi_uc *buffer, int len) { start_mem(buffer, len); return bmp_test(); } // returns 0..31 for the highest set bit static int high_bit(unsigned int z) { int n=0; if (z == 0) return -1; if (z >= 0x10000) n += 16, z >>= 16; if (z >= 0x00100) n += 8, z >>= 8; if (z >= 0x00010) n += 4, z >>= 4; if (z >= 0x00004) n += 2, z >>= 2; if (z >= 0x00002) n += 1, z >>= 1; return n; } static int bitcount(unsigned int a) { a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2 a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4 a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits a = (a + (a >> 8)); // max 16 per 8 bits a = (a + (a >> 16)); // max 32 per 8 bits return a & 0xff; } static int shiftsigned(int v, int shift, int bits) { int result; int z=0; if (shift < 0) v <<= -shift; else v >>= shift; result = v; z = bits; while (z < 8) { result += v >> z; z += bits; } return result; } static stbi_uc *bmp_load(int *x, int *y, int *comp, int req_comp) { unsigned int mr=0,mg=0,mb=0,ma=0; stbi_uc pal[256][4]; int psize=0,i,j,compress=0,width; int bpp, flip_vertically, pad, target, offset, hsz; if (get8() != 'B' || get8() != 'M') return ep("not BMP"); get32le(); // discard filesize get16le(); // discard reserved get16le(); // discard reserved offset = get32le(); hsz = get32le(); if (hsz != 12 && hsz != 40 && hsz != 108) return ep("unknown BMP"); failure_reason = "bad BMP"; img_x = get32le(); img_y = get32le(); if (get16le() != 1) return 0; bpp = get16le(); if (bpp == 1) return ep("monochrome"); flip_vertically = img_y > 0; img_y = abs(img_y); if (hsz == 12) { if (bpp < 24) psize = (offset - 14 - 24) / 3; } else { compress = get32(); if (compress == 1 || compress == 2) return ep("BMP RLE"); get32le(); // discard sizeof get32le(); // discard hres get32le(); // discard vres get32le(); // discard colorsused get32le(); // discard max important if (hsz == 40) { if (bpp == 16 || bpp == 32) { if (compress == 0) { if (bpp == 32) { mr = 0xff << 16; mg = 0xff << 8; mb = 0xff << 0; } else { mr = 31 << 10; mg = 31 << 5; mb = 31 << 0; } } else if (compress == 3) { mr = get32le(); mg = get32le(); mb = get32le(); } else return NULL; } } else { assert(hsz == 108); mr = get32le(); mg = get32le(); mb = get32le(); ma = get32le(); get32le(); // discard color space for (i=0; i < 12; ++i) get32le(); // discard color space parameters } if (bpp < 16) psize = (offset - 14 - hsz) >> 2; } img_n = ma ? 4 : 3; if (req_comp && req_comp >= 3) // we can directly decode 3 or 4 target = req_comp; else target = img_n; // if they want monochrome, we'll post-convert out = (stbi_uc *) malloc(target * img_x * img_y); if (!out) return ep("outofmem"); if (bpp < 16) { int z=0; if (psize == 0 || psize > 256) return ep("invalid"); for (i=0; i < psize; ++i) { pal[i][2] = get8(); pal[i][1] = get8(); pal[i][0] = get8(); if (hsz != 12) get8(); pal[i][3] = 255; } skip(offset - 14 - hsz - psize * (hsz == 12 ? 3 : 4)); if (bpp == 4) width = (img_x + 1) >> 1; else if (bpp == 8) width = img_x; else return ep("bad bpp"); pad = (-width)&3; for (j=0; j < (int) img_y; ++j) { for (i=0; i < (int) img_x; i += 2) { int v=get8(),v2; if (bpp == 4) { v2 = v & 15; v >>= 4; } out[z++] = pal[v][0]; out[z++] = pal[v][1]; out[z++] = pal[v][2]; if (target == 4) out[z++] = 255; if (i+1 == (int) img_x) break; v = (bpp == 8) ? get8() : v2; out[z++] = pal[v][0]; out[z++] = pal[v][1]; out[z++] = pal[v][2]; if (target == 4) out[z++] = 255; } skip(pad); } } else { int rshift,gshift,bshift,ashift,rcount,gcount,bcount,acount; int z = 0; int easy=0; skip(offset - 14 - hsz); if (bpp == 24) width = 3 * img_x; else if (bpp == 16) width = 2*img_x; else /* bpp = 32 and pad = 0 */ width=0; pad = (-width) & 3; if (bpp == 24) { easy = 1; } else if (bpp == 32) { if (mb == 0xff && mg == 0xff00 && mr == 0xff000000 && ma == 0xff000000) easy = 2; } if (!easy) { if (!mr || !mg || !mb) return ep("bad masks"); // right shift amt to put high bit in position #7 rshift = high_bit(mr)-7; rcount = bitcount(mr); gshift = high_bit(mg)-7; gcount = bitcount(mr); bshift = high_bit(mb)-7; bcount = bitcount(mr); ashift = high_bit(ma)-7; acount = bitcount(mr); } for (j=0; j < (int) img_y; ++j) { if (easy) { for (i=0; i < (int) img_x; ++i) { int a; out[z+2] = get8(); out[z+1] = get8(); out[z+0] = get8(); z += 3; a = (easy == 2 ? get8() : 255); if (target == 4) out[z++] = a; } } else { for (i=0; i < (int) img_x; ++i) { unsigned long v = (bpp == 16 ? get16le() : get32le()); int a; out[z++] = shiftsigned(v & mr, rshift, rcount); out[z++] = shiftsigned(v & mg, gshift, gcount); out[z++] = shiftsigned(v & mb, bshift, bcount); a = (ma ? shiftsigned(v & ma, ashift, acount) : 255); if (target == 4) out[z++] = a; } } skip(pad); } } if (flip_vertically) { stbi_uc t; for (j=0; j < (int) img_y>>1; ++j) { stbi_uc *p1 = out + j *img_x*target; stbi_uc *p2 = out + (img_y-1-j)*img_x*target; for (i=0; i < (int) img_x*target; ++i) { t = p1[i], p1[i] = p2[i], p2[i] = t; } } } if (req_comp && req_comp != target) { out = convert_format(out, target, req_comp); if (out == NULL) return out; // convert_format frees input on failure } *x = img_x; *y = img_y; if (comp) *comp = target; return out; } stbi_uc *stbi_bmp_load (char *filename, int *x, int *y, int *comp, int req_comp) { stbi_uc *data; FILE *f = fopen(filename, "rb"); if (!f) return NULL; data = bmp_load(x,y,comp,req_comp); fclose(f); return data; } stbi_uc *stbi_bmp_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp) { start_file(f); return bmp_load(x,y,comp,req_comp); } stbi_uc *stbi_bmp_load_from_memory (stbi_uc *buffer, int len, int *x, int *y, int *comp, int req_comp) { start_mem(buffer, len); return bmp_load(x,y,comp,req_comp); } /////////////////////// write image /////////////////////// #ifndef STBI_NO_WRITE static void write8(FILE *f, int x) { uint8 z = (uint8) x; fwrite(&z,1,1,f); } static void writefv(FILE *f, char *fmt, va_list v) { while (*fmt) { switch (*fmt++) { case ' ': break; case '1': { uint8 x = va_arg(v, int); write8(f,x); break; } case '2': { int16 x = va_arg(v, int); write8(f,x); write8(f,x>>8); break; } case '4': { int32 x = va_arg(v, int); write8(f,x); write8(f,x>>8); write8(f,x>>16); write8(f,x>>24); break; } default: assert(0); va_end(v); return; } } } static void writef(FILE *f, char *fmt, ...) { va_list v; va_start(v, fmt); writefv(f,fmt,v); va_end(v); } static void write_pixels(FILE *f, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad) { uint8 bg[3] = { 255, 0, 255}, px[3]; uint32 zero = 0; int i,j,k, j_end; if (vdir < 0) j_end = -1, j = y-1; else j_end = y, j = 0; for (; j != j_end; j += vdir) { for (i=0; i < x; ++i) { uint8 *d = (uint8 *) data + (j*x+i)*comp; if (write_alpha < 0) fwrite(&d[comp-1], 1, 1, f); switch (comp) { case 1: case 2: writef(f, "111", d[0],d[0],d[0]); break; case 4: if (!write_alpha) { for (k=0; k < 3; ++k) px[k] = bg[k] + ((d[k] - bg[k]) * d[3])/255; writef(f, "111", px[1-rgb_dir],px[1],px[1+rgb_dir]); break; } /* FALLTHROUGH */ case 3: writef(f, "111", d[1-rgb_dir],d[1],d[1+rgb_dir]); break; } if (write_alpha > 0) fwrite(&d[comp-1], 1, 1, f); } fwrite(&zero,scanline_pad,1,f); } } static int outfile(char *filename, int rgb_dir, int vdir, int x, int y, int comp, void *data, int alpha, int pad, char *fmt, ...) { FILE *f = fopen(filename, "wb"); if (f) { va_list v; va_start(v, fmt); writefv(f, fmt, v); va_end(v); write_pixels(f,rgb_dir,vdir,x,y,comp,data,alpha,pad); fclose(f); } return f != NULL; } int stbi_write_bmp(char *filename, int x, int y, int comp, void *data) { int pad = (-x*3) & 3; return outfile(filename,-1,-1,x,y,comp,data,0,pad, "11 4 22 4" "4 44 22 444444", 'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40, // file header 40, x,y, 1,24, 0,0,0,0,0,0); // bitmap header } int stbi_write_tga(char *filename, int x, int y, int comp, void *data) { int has_alpha = !(comp & 1); return outfile(filename, -1,-1, x, y, comp, data, has_alpha, 0, "111 221 2222 11", 0,0,2, 0,0,0, 0,0,x,y, 24+8*has_alpha, 8*has_alpha); } // any other image formats that do interleaved rgb data? // PNG: requires adler32,crc32 -- significant amount of code // PSD: no, channels output separately // TIFF: no, stripwise-interleaved... i think #endif