png: support more color types; fix idat sequencing
This commit is contained in:
K. Lange
parent
69324a4e3d
commit
431a6aaf2a
283
lib/png.c
283
lib/png.c
@ -98,6 +98,8 @@ static uint8_t _get(struct inflate_context * ctx) {
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unsigned int size = read_32(c->f);
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unsigned int type = read_32(c->f);
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c->size = size;
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if (type != PNG_IDAT) {
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/* This isn't an IDAT? That's wrong! */
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fprintf(stderr, "And this is the wrong type (0x%x), I'm just bailing.\n", type);
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@ -131,6 +133,202 @@ static int paeth(int a, int b, int c) {
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return c;
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}
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static void write_pixel(struct png_ctx * c, uint32_t color) {
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SPRITE((c->sprite), (c->x), (c->y)) = color;
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/* Reset the short buffer */
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c->buf_off = 0;
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/* Advance to next pixel */
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c->x++;
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if (c->x == (int)c->width) {
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/* Advance to next line; next read is scanline filter type */
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c->x = -1;
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c->y++;
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}
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}
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static void process_pixel_type_6(struct png_ctx * c) {
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/*
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* Obtain pixel data from short buffer;
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* For color type 6, this is always in R G B A order in the
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* bytestream, so we don't have to worry about subpixel ordering
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* or weird color masks.
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*/
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unsigned int r = c->buffer[0];
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unsigned int g = c->buffer[1];
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unsigned int b = c->buffer[2];
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unsigned int a = c->buffer[3];
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/* Apply filters */
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if (c->sf == PNG_FILTER_SUB) {
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/* Add raw value to the pixel on the left */
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if (c->x > 0) {
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uint32_t left = SPRITE((c->sprite), (c->x - 1), (c->y));
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r += _RED(left);
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g += _GRE(left);
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b += _BLU(left);
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a += _ALP(left);
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}
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} else if (c->sf == PNG_FILTER_UP) {
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/* Add raw value to the pixel above */
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if (c->y > 0) {
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uint32_t up = SPRITE((c->sprite), (c->x), (c->y - 1));
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r += _RED(up);
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g += _GRE(up);
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b += _BLU(up);
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a += _ALP(up);
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}
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} else if (c->sf == PNG_FILTER_AVG) {
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/* Add raw value to the average of the pixel above and left */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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r += ((int)_RED(left) + (int)_RED(up)) / 2;
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g += ((int)_GRE(left) + (int)_GRE(up)) / 2;
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b += ((int)_BLU(left) + (int)_BLU(up)) / 2;
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a += ((int)_ALP(left) + (int)_ALP(up)) / 2;
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} else if (c->sf == PNG_FILTER_PAETH) {
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/* Use the Paeth predictor */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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uint32_t upleft = (c->x > 0 && c->y > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y - 1)) : 0;
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r = ((int)r + paeth((int)_RED(left),(int)_RED(up),(int)_RED(upleft))) % 256;
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g = ((int)g + paeth((int)_GRE(left),(int)_GRE(up),(int)_GRE(upleft))) % 256;
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b = ((int)b + paeth((int)_BLU(left),(int)_BLU(up),(int)_BLU(upleft))) % 256;
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a = ((int)a + paeth((int)_ALP(left),(int)_ALP(up),(int)_ALP(upleft))) % 256;
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}
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/* Write new pixel to the image */
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write_pixel(c, rgba(r,g,b,a));
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}
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static void process_pixel_type_2(struct png_ctx * c) {
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/*
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* Obtain pixel data from short buffer;
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* For color type 6, this is always in R G B A order in the
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* bytestream, so we don't have to worry about subpixel ordering
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* or weird color masks.
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*/
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unsigned int r = c->buffer[0];
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unsigned int g = c->buffer[1];
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unsigned int b = c->buffer[2];
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/* Apply filters */
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if (c->sf == PNG_FILTER_SUB) {
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/* Add raw value to the pixel on the left */
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if (c->x > 0) {
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uint32_t left = SPRITE((c->sprite), (c->x - 1), (c->y));
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r += _RED(left);
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g += _GRE(left);
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b += _BLU(left);
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}
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} else if (c->sf == PNG_FILTER_UP) {
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/* Add raw value to the pixel above */
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if (c->y > 0) {
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uint32_t up = SPRITE((c->sprite), (c->x), (c->y - 1));
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r += _RED(up);
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g += _GRE(up);
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b += _BLU(up);
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}
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} else if (c->sf == PNG_FILTER_AVG) {
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/* Add raw value to the average of the pixel above and left */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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r += ((int)_RED(left) + (int)_RED(up)) / 2;
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g += ((int)_GRE(left) + (int)_GRE(up)) / 2;
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b += ((int)_BLU(left) + (int)_BLU(up)) / 2;
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} else if (c->sf == PNG_FILTER_PAETH) {
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/* Use the Paeth predictor */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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uint32_t upleft = (c->x > 0 && c->y > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y - 1)) : 0;
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r = ((int)r + paeth((int)_RED(left),(int)_RED(up),(int)_RED(upleft))) % 256;
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g = ((int)g + paeth((int)_GRE(left),(int)_GRE(up),(int)_GRE(upleft))) % 256;
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b = ((int)b + paeth((int)_BLU(left),(int)_BLU(up),(int)_BLU(upleft))) % 256;
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}
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/* Write new pixel to the image */
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write_pixel(c, rgb(r,g,b));
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}
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static void process_pixel_type_4(struct png_ctx * c) {
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/*
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* Obtain pixel data from short buffer;
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* For color type 6, this is always in R G B A order in the
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* bytestream, so we don't have to worry about subpixel ordering
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* or weird color masks.
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*/
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unsigned int b = c->buffer[0];
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unsigned int a = c->buffer[1];
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/* Apply filters */
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if (c->sf == PNG_FILTER_SUB) {
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/* Add raw value to the pixel on the left */
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if (c->x > 0) {
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uint32_t left = SPRITE((c->sprite), (c->x - 1), (c->y));
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b += _BLU(left);
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a += _ALP(left);
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}
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} else if (c->sf == PNG_FILTER_UP) {
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/* Add raw value to the pixel above */
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if (c->y > 0) {
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uint32_t up = SPRITE((c->sprite), (c->x), (c->y - 1));
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b += _BLU(up);
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a += _ALP(up);
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}
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} else if (c->sf == PNG_FILTER_AVG) {
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/* Add raw value to the average of the pixel above and left */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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b += ((int)_BLU(left) + (int)_BLU(up)) / 2;
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a += ((int)_ALP(left) + (int)_ALP(up)) / 2;
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} else if (c->sf == PNG_FILTER_PAETH) {
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/* Use the Paeth predictor */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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uint32_t upleft = (c->x > 0 && c->y > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y - 1)) : 0;
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b = ((int)b + paeth((int)_BLU(left),(int)_BLU(up),(int)_BLU(upleft))) % 256;
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a = ((int)a + paeth((int)_ALP(left),(int)_ALP(up),(int)_ALP(upleft))) % 256;
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}
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/* Write new pixel to the image */
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write_pixel(c, rgba(b,b,b,a));
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}
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static void process_pixel_type_0(struct png_ctx * c) {
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unsigned int b = c->buffer[0];
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if (c->sf == PNG_FILTER_SUB) {
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if (c->x > 0) {
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uint32_t left = SPRITE((c->sprite), (c->x - 1), (c->y));
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b += _BLU(left);
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}
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} else if (c->sf == PNG_FILTER_UP) {
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if (c->y > 0) {
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uint32_t up = SPRITE((c->sprite), (c->x), (c->y - 1));
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b += _BLU(up);
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}
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} else if (c->sf == PNG_FILTER_AVG) {
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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b += ((int)_BLU(left) + (int)_BLU(up)) / 2;
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} else if (c->sf == PNG_FILTER_PAETH) {
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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uint32_t upleft = (c->x > 0 && c->y > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y - 1)) : 0;
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b = ((int)b + paeth((int)_BLU(left),(int)_BLU(up),(int)_BLU(upleft))) % 256;
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}
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/* Write new pixel to the image */
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write_pixel(c, rgb(b,b,b));
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}
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/**
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* Handle decompressed output from the inflater
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*
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@ -151,71 +349,24 @@ static void _write(struct inflate_context * ctx, unsigned int sym) {
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/* Reset the buffer, advance to the beginning of the actual scanline */
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c->x = 0;
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c->buf_off = 0;
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} else if (c->buf_off == 4) {
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/*
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* Obtain pixel data from short buffer;
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* For color type 6, this is always in R G B A order in the
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* bytestream, so we don't have to worry about subpixel ordering
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* or weird color masks.
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*/
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unsigned int r = c->buffer[0];
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unsigned int g = c->buffer[1];
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unsigned int b = c->buffer[2];
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unsigned int a = c->buffer[3];
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} else if (c->buf_off == 1 && c->color_type == 0) {
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process_pixel_type_0(c);
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} else if (c->buf_off == 2 && c->color_type == 4) {
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process_pixel_type_4(c);
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} else if (c->buf_off == 3 && c->color_type == 2) {
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process_pixel_type_2(c);
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} else if (c->buf_off == 4 && c->color_type == 6) {
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process_pixel_type_6(c);
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}
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}
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/* Apply filters */
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if (c->sf == PNG_FILTER_SUB) {
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/* Add raw value to the pixel on the left */
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if (c->x > 0) {
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uint32_t left = SPRITE((c->sprite), (c->x - 1), (c->y));
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r += _RED(left);
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g += _GRE(left);
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b += _BLU(left);
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a += _ALP(left);
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}
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} else if (c->sf == PNG_FILTER_UP) {
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/* Add raw value to the pixel above */
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if (c->y > 0) {
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uint32_t up = SPRITE((c->sprite), (c->x), (c->y - 1));
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r += _RED(up);
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g += _GRE(up);
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b += _BLU(up);
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a += _ALP(up);
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}
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} else if (c->sf == PNG_FILTER_AVG) {
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/* Add raw value to the average of the pixel above and left */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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r += ((int)_RED(left) + (int)_RED(up)) / 2;
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g += ((int)_GRE(left) + (int)_GRE(up)) / 2;
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b += ((int)_BLU(left) + (int)_BLU(up)) / 2;
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a += ((int)_ALP(left) + (int)_ALP(up)) / 2;
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} else if (c->sf == PNG_FILTER_PAETH) {
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/* Use the Paeth predictor */
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uint32_t left = (c->x > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y)) : 0;
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uint32_t up = (c->y > 0) ? SPRITE((c->sprite), (c->x), (c->y - 1)) : 0;
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uint32_t upleft = (c->x > 0 && c->y > 0) ? SPRITE((c->sprite), (c->x - 1), (c->y - 1)) : 0;
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r = ((int)r + paeth((int)_RED(left),(int)_RED(up),(int)_RED(upleft))) % 256;
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g = ((int)g + paeth((int)_GRE(left),(int)_GRE(up),(int)_GRE(upleft))) % 256;
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b = ((int)b + paeth((int)_BLU(left),(int)_BLU(up),(int)_BLU(upleft))) % 256;
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a = ((int)a + paeth((int)_ALP(left),(int)_ALP(up),(int)_ALP(upleft))) % 256;
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}
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/* Write new pixel to the image */
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SPRITE((c->sprite), (c->x), (c->y)) = rgba(r,g,b,a);
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/* Reset the short buffer */
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c->buf_off = 0;
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/* Advance to next pixel */
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c->x++;
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if (c->x == (int)c->width) {
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/* Advance to next line; next read is scanline filter type */
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c->x = -1;
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c->y++;
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}
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static int color_type_has_alpha(int c) {
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switch (c) {
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case 4:
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case 6:
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return ALPHA_EMBEDDED;
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default:
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return 0;
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}
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}
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@ -275,14 +426,14 @@ int load_sprite_png(sprite_t * sprite, char * filename) {
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if (c.interlace != 0 && c.interlace != 1) return 1;
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if (c.bit_depth != 8) return 1; /* Sorry */
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if (c.color_type != 6) return 1; /* Sorry */
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if (c.color_type < 0 || c.color_type > 6 || (c.color_type & 1)) return 1; /* Sorry, no indexed support */
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/* Allocate space */
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sprite->width = c.width;
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sprite->height = c.height;
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sprite->bitmap = malloc(sizeof(uint32_t) * sprite->width * sprite->height);
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sprite->masks = NULL;
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sprite->alpha = (c.color_type == 4 || c.color_type == 6) ? ALPHA_EMBEDDED : 0;
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sprite->alpha = color_type_has_alpha(c.color_type);
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sprite->blank = 0;
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