Added code to read GIF files from memory (GitHub issue #33, 2/2)
This commit is contained in:
Matthias Melcher
parent
86893a90cb
commit
1ba9e64ba9
@ -30,9 +30,15 @@
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*/
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class FL_EXPORT Fl_GIF_Image : public Fl_Pixmap {
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public:
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public:
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Fl_GIF_Image(const char* filename);
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Fl_GIF_Image(const char* filename, const unsigned char *data);
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protected:
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void read(class GIFReader &rdr);
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};
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#endif
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@ -77,8 +77,80 @@
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typedef unsigned char uchar;
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#define NEXTBYTE (uchar)getc(GifFile)
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#define GETSHORT(var) var = NEXTBYTE; var += NEXTBYTE << 8
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//
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// Local reader class...
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//
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class GIFReader
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{
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public:
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GIFReader() :
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pIsFile(0), pIsData(0),
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pFile(0L), pData(0L), pStart(0L),
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pName(0L)
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{ }
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int open(const char *filename) {
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if (filename)
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pName = strdup(filename);
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if ((pFile = fl_fopen(filename, "rb")) == NULL) {
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return -1;
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} else {
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pIsFile = 1;
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return 0;
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}
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}
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int open(const char *imagename, const unsigned char *data) {
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if (imagename)
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pName = strdup(imagename);
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if (data) {
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pStart = pData = data;
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pIsData = 1;
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return 0;
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} else {
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return -1;
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}
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}
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~GIFReader() {
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if (pIsFile && pFile) {
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fclose(pFile);
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}
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if (pName)
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::free(pName);
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}
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uchar read_byte() {
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if (pIsFile) {
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return getc(pFile);
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} else if (pIsData) {
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return *pData++;
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} else {
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return 0;
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}
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}
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// 'read_word()' - Read a 16-bit unsigned integer.
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unsigned short read_word() {
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unsigned char b0, b1; // Bytes from file
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if (pIsFile) {
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b0 = (uchar)getc(pFile);
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b1 = (uchar)getc(pFile);
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return ((b1 << 8) | b0);
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} else if (pIsData) {
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b0 = *pData++;
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b1 = *pData++;
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return ((b1 << 8) | b0);
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} else {
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return 0;
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}
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}
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const char *name() { return pName; }
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private:
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char pIsFile;
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char pIsData;
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FILE *pFile;
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const unsigned char *pData;
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const unsigned char *pStart;
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char *pName;
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};
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/**
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The constructor loads the named GIF image.
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@ -91,36 +163,58 @@ typedef unsigned char uchar;
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GIF format could not be decoded, and ERR_NO_IMAGE if the image could not
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be loaded for another reason.
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*/
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Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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FILE *GifFile; // File to read
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char **new_data; // Data array
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if ((GifFile = fl_fopen(infname, "rb")) == NULL) {
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Fl_GIF_Image::Fl_GIF_Image(const char *infname) :
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Fl_Pixmap((char *const*)0)
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{
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GIFReader f;
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if (f.open(infname)==-1) {
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Fl::error("Fl_GIF_Image: Unable to open %s!", infname);
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ld(ERR_FILE_ACCESS);
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return;
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} else {
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read(f);
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}
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}
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{char b[6];
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if (fread(b,1,6,GifFile)<6) {
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fclose(GifFile);
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ld(ERR_FILE_ACCESS);
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return; /* quit on eof */
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}
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if (b[0]!='G' || b[1]!='I' || b[2] != 'F') {
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fclose(GifFile);
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Fl::error("Fl_GIF_Image: %s is not a GIF file.\n", infname);
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/**
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The constructor loads the named GIF image.
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\param[in] bmp the name of the bitmap
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\param[in] data a pointer to the BMP data in memory. There is no checking for buffer overruns
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\see Fl_BMP_Image::Fl_BMP_Image(const char *bmp)
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*/
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Fl_GIF_Image::Fl_GIF_Image(const char *gif, const unsigned char *data) :
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Fl_Pixmap((char *const*)0)
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{
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GIFReader d;
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if (d.open(gif, data)==-1) {
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ld(ERR_FORMAT);
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return;
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} else {
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read(d);
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}
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if (b[3]!='8' || b[4]>'9' || b[5]!= 'a')
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Fl::warning("%s is version %c%c%c.",infname,b[3],b[4],b[5]);
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}
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void Fl_GIF_Image::read(GIFReader &rdr)
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{
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char **new_data; // Data array
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{char b[6] = { 0 };
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for (int i=0; i<6; ++i) b[i] = rdr.read_byte();
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if (b[0]!='G' || b[1]!='I' || b[2] != 'F') {
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Fl::error("Fl_GIF_Image: %s is not a GIF file.\n", rdr.name());
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ld(ERR_FORMAT);
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return;
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}
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if (b[3]!='8' || b[4]>'9' || b[5]!= 'a')
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Fl::warning("%s is version %c%c%c.",rdr.name(),b[3],b[4],b[5]);
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}
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int Width; GETSHORT(Width);
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int Height; GETSHORT(Height);
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int Width = rdr.read_word();
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int Height = rdr.read_word();
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uchar ch = NEXTBYTE;
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uchar ch = rdr.read_byte();
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char HasColormap = ((ch & 0x80) != 0);
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int BitsPerPixel = (ch & 7) + 1;
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int ColorMapSize;
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@ -131,18 +225,18 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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}
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// int OriginalResolution = ((ch>>4)&7)+1;
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// int SortedTable = (ch&8)!=0;
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ch = NEXTBYTE; // Background Color index
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ch = NEXTBYTE; // Aspect ratio is N/64
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ch = rdr.read_byte(); // Background Color index
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ch = rdr.read_byte(); // Aspect ratio is N/64
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// Read in global colormap:
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uchar transparent_pixel = 0;
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char has_transparent = 0;
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uchar Red[256], Green[256], Blue[256]; /* color map */
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if (HasColormap) {
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for (int i=0; i < ColorMapSize; i++) {
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Red[i] = NEXTBYTE;
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Green[i] = NEXTBYTE;
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Blue[i] = NEXTBYTE;
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for (int i=0; i < ColorMapSize; i++) {
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Red[i] = rdr.read_byte();
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Green[i] = rdr.read_byte();
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Blue[i] = rdr.read_byte();
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}
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}
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@ -151,10 +245,9 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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for (;;) {
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int i = NEXTBYTE;
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int i = rdr.read_byte();
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if (i<0) {
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fclose(GifFile);
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Fl::error("Fl_GIF_Image: %s - unexpected EOF",infname);
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Fl::error("Fl_GIF_Image: %s - unexpected EOF", rdr.name());
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w(0); h(0); d(0); ld(ERR_FORMAT);
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return;
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}
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@ -164,50 +257,50 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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if (i == 0x21) { // a "gif extension"
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ch = NEXTBYTE;
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blocklen = NEXTBYTE;
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ch = rdr.read_byte();
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blocklen = rdr.read_byte();
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if (ch==0xF9 && blocklen==4) { // Netscape animation extension
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char bits;
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bits = NEXTBYTE;
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getc(GifFile); getc(GifFile); // GETSHORT(delay);
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transparent_pixel = NEXTBYTE;
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if (bits & 1) has_transparent = 1;
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blocklen = NEXTBYTE;
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char bits;
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bits = rdr.read_byte();
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rdr.read_word(); // GETSHORT(delay);
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transparent_pixel = rdr.read_byte();
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if (bits & 1) has_transparent = 1;
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blocklen = rdr.read_byte();
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} else if (ch == 0xFF) { // Netscape repeat count
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;
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;
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} else if (ch != 0xFE) { //Gif Comment
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Fl::warning("%s: unknown gif extension 0x%02x.", infname, ch);
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Fl::warning("%s: unknown gif extension 0x%02x.", rdr.name(), ch);
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}
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} else if (i == 0x2c) { // an image
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ch = NEXTBYTE; ch = NEXTBYTE; // GETSHORT(x_position);
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ch = NEXTBYTE; ch = NEXTBYTE; // GETSHORT(y_position);
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GETSHORT(Width);
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GETSHORT(Height);
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ch = NEXTBYTE;
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ch = rdr.read_byte(); ch = rdr.read_byte(); // GETSHORT(x_position);
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ch = rdr.read_byte(); ch = rdr.read_byte(); // GETSHORT(y_position);
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Width = rdr.read_word();
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Height = rdr.read_word();
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ch = rdr.read_byte();
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Interlace = ((ch & 0x40) != 0);
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if (ch & 0x80) { // image has local color table
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BitsPerPixel = (ch & 7) + 1;
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ColorMapSize = 2 << (ch & 7);
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for (i=0; i < ColorMapSize; i++) {
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Red[i] = NEXTBYTE;
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Green[i] = NEXTBYTE;
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Blue[i] = NEXTBYTE;
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}
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BitsPerPixel = (ch & 7) + 1;
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ColorMapSize = 2 << (ch & 7);
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for (i=0; i < ColorMapSize; i++) {
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Red[i] = rdr.read_byte();
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Green[i] = rdr.read_byte();
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Blue[i] = rdr.read_byte();
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}
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}
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CodeSize = NEXTBYTE+1;
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CodeSize = rdr.read_byte()+1;
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break; // okay, this is the image we want
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} else {
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Fl::warning("%s: unknown gif code 0x%02x", infname, i);
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Fl::warning("%s: unknown gif code 0x%02x", rdr.name(), i);
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blocklen = 0;
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}
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// skip the data:
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while (blocklen>0) {while (blocklen--) {ch = NEXTBYTE;} blocklen=NEXTBYTE;}
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while (blocklen>0) {while (blocklen--) {ch = rdr.read_byte();} blocklen=rdr.read_byte();}
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}
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if (BitsPerPixel >= CodeSize)
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@ -222,7 +315,7 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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// first two color table entries should be black and white.
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if (ColorMapSize == 0) { // no global and no local color table
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Fl::warning("%s does not have a color table, using default.\n", infname);
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Fl::warning("%s does not have a color table, using default.\n", rdr.name());
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BitsPerPixel = CodeSize - 1;
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ColorMapSize = 1 << BitsPerPixel;
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Red[0] = Green[0] = Blue[0] = 0; // black
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@ -257,32 +350,32 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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short int Prefix[4096];
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uchar Suffix[4096];
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int blocklen = NEXTBYTE;
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uchar thisbyte = NEXTBYTE; blocklen--;
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int blocklen = rdr.read_byte();
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uchar thisbyte = rdr.read_byte(); blocklen--;
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int frombit = 0;
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for (;;) {
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/* Fetch the next code from the raster data stream. The codes can be
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* any length from 3 to 12 bits, packed into 8-bit bytes, so we have to
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* maintain our location as a pointer and a bit offset.
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* In addition, gif adds totally useless and annoying block counts
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* that must be correctly skipped over. */
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/* Fetch the next code from the raster data stream. The codes can be
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* any length from 3 to 12 bits, packed into 8-bit bytes, so we have to
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* maintain our location as a pointer and a bit offset.
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* In addition, gif adds totally useless and annoying block counts
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* that must be correctly skipped over. */
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int CurCode = thisbyte;
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if (frombit+CodeSize > 7) {
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if (blocklen <= 0) {
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blocklen = NEXTBYTE;
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if (blocklen <= 0) break;
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blocklen = rdr.read_byte();
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if (blocklen <= 0) break;
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}
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thisbyte = NEXTBYTE; blocklen--;
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thisbyte = rdr.read_byte(); blocklen--;
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CurCode |= thisbyte<<8;
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}
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if (frombit+CodeSize > 15) {
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if (blocklen <= 0) {
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blocklen = NEXTBYTE;
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if (blocklen <= 0) break;
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blocklen = rdr.read_byte();
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if (blocklen <= 0) break;
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}
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thisbyte = NEXTBYTE; blocklen--;
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thisbyte = rdr.read_byte(); blocklen--;
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CurCode |= thisbyte<<16;
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}
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CurCode = (CurCode>>frombit)&ReadMask;
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@ -303,23 +396,23 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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int i;
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if (CurCode < FreeCode) i = CurCode;
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else if (CurCode == FreeCode) {*tp++ = (uchar)FinChar; i = OldCode;}
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else {Fl::error("Fl_GIF_Image: %s - LZW Barf!", infname); break;}
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else {Fl::error("Fl_GIF_Image: %s - LZW Barf!", rdr.name()); break;}
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while (i >= ColorMapSize) {*tp++ = Suffix[i]; i = Prefix[i];}
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*tp++ = FinChar = i;
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do {
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*p++ = *--tp;
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if (p >= eol) {
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if (!Interlace) YC++;
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else switch (Pass) {
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case 0: YC += 8; if (YC >= Height) {Pass++; YC = 4;} break;
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case 1: YC += 8; if (YC >= Height) {Pass++; YC = 2;} break;
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case 2: YC += 4; if (YC >= Height) {Pass++; YC = 1;} break;
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case 3: YC += 2; break;
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}
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if (YC>=Height) YC=0; /* cheap bug fix when excess data */
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p = Image + YC*Width;
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eol = p+Width;
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if (!Interlace) YC++;
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else switch (Pass) {
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case 0: YC += 8; if (YC >= Height) {Pass++; YC = 4;} break;
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case 1: YC += 8; if (YC >= Height) {Pass++; YC = 2;} break;
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case 2: YC += 4; if (YC >= Height) {Pass++; YC = 1;} break;
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case 3: YC += 2; break;
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}
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if (YC>=Height) YC=0; /* cheap bug fix when excess data */
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p = Image + YC*Width;
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eol = p+Width;
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}
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} while (tp > OutCode);
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@ -328,11 +421,11 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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Suffix[FreeCode] = FinChar;
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FreeCode++;
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if (FreeCode > ReadMask) {
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if (CodeSize < 12) {
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CodeSize++;
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ReadMask = (1 << CodeSize) - 1;
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}
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else FreeCode--;
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if (CodeSize < 12) {
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CodeSize++;
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ReadMask = (1 << CodeSize) - 1;
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}
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else FreeCode--;
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}
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}
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OldCode = CurCode;
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@ -385,7 +478,7 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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// write the first line of xpm data (use suffix as temp array):
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int length = sprintf((char*)(Suffix),
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"%d %d %d %d",Width,Height,-numcolors,1);
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"%d %d %d %d",Width,Height,-numcolors,1);
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new_data[0] = new char[length+1];
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strcpy(new_data[0], (char*)Suffix);
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@ -413,8 +506,6 @@ Fl_GIF_Image::Fl_GIF_Image(const char *infname) : Fl_Pixmap((char *const*)0) {
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alloc_data = 1;
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delete[] Image;
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fclose(GifFile);
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}
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