From d64ed70d92d39258671f83e88e63ea182f22719a Mon Sep 17 00:00:00 2001 From: Vladimir Ananiev Date: Sun, 23 Dec 2007 01:08:27 +0300 Subject: [PATCH 11/11] Transparency in PNG support Signed-off-by: Vladimir Ananiev --- src/engine/devdraw.c | 62 +++++++++++++++++++---------------- src/engine/image_png.c | 84 ++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 101 insertions(+), 45 deletions(-) diff --git a/src/engine/devdraw.c b/src/engine/devdraw.c index c9fd770..c30bdc1 100644 --- a/src/engine/devdraw.c +++ b/src/engine/devdraw.c @@ -777,7 +777,7 @@ GdDrawImage(PSD psd, MWCOORD x, MWCOORD y, PMWIMAGEHDR pimage) MWPIXELVAL pixel; int clip; int extra, linesize; - int rgborder; + int rgborder, alpha; MWCOLORVAL cr; MWCOORD yoff; unsigned long transcolor; @@ -880,34 +880,40 @@ GdDrawImage(PSD psd, MWCOORD x, MWCOORD y, PMWIMAGEHDR pimage) | ((cr & 0x000000FFUL) << 16); } #endif - switch (psd->pixtype) { - case MWPF_PALETTE: - default: - pixel = GdFindColor(psd, cr); - break; - case MWPF_TRUECOLOR8888: - pixel = COLOR2PIXEL8888(cr); - break; - case MWPF_TRUECOLOR0888: - case MWPF_TRUECOLOR888: - pixel = COLOR2PIXEL888(cr); - break; - case MWPF_TRUECOLOR565: - pixel = COLOR2PIXEL565(cr); - break; - case MWPF_TRUECOLOR555: - pixel = COLOR2PIXEL555(cr); - break; - case MWPF_TRUECOLOR332: - pixel = COLOR2PIXEL332(cr); - break; - case MWPF_TRUECOLOR233: - pixel = COLOR2PIXEL233(cr); - break; - } + /* alpha channel handling + * FIXME - just visible or not, no alpha blending yet */ + alpha = (cr >> 24); + if (alpha != 0) { /* skip if pixel is fully transparent*/ + if (clip == CLIP_VISIBLE || GdClipPoint(psd, x, y)) { + switch (psd->pixtype) { + case MWPF_PALETTE: + default: + pixel = GdFindColor(psd, cr); + break; + case MWPF_TRUECOLOR8888: + pixel = COLOR2PIXEL8888(cr); + break; + case MWPF_TRUECOLOR0888: + case MWPF_TRUECOLOR888: + pixel = COLOR2PIXEL888(cr); + break; + case MWPF_TRUECOLOR565: + pixel = COLOR2PIXEL565(cr); + break; + case MWPF_TRUECOLOR555: + pixel = COLOR2PIXEL555(cr); + break; + case MWPF_TRUECOLOR332: + pixel = COLOR2PIXEL332(cr); + break; + case MWPF_TRUECOLOR233: + pixel = COLOR2PIXEL233(cr); + break; + } + psd->DrawPixel(psd, x, y, pixel); - if (clip == CLIP_VISIBLE || GdClipPoint(psd, x, y)) - psd->DrawPixel(psd, x, y, pixel); + } + } if (x++ == maxx) { x = minx; diff --git a/src/engine/image_png.c b/src/engine/image_png.c index 0ae83f6..872446e 100644 --- a/src/engine/image_png.c +++ b/src/engine/image_png.c @@ -9,6 +9,9 @@ * potentially store the image more efficiently by taking note of the image * type and depth and acting accordingly. Similarly, > 8 bits per channel, * gamma correction, etc. are not supported. + * + * 2007-Nov-15 - Vladimir Ananiev (vovan888 at gmail com) + * alpha channel, gamma correction added - ripped from pngm2pnm.c */ #include #include @@ -43,7 +46,12 @@ GdDecodePNG(buffer_t * src, PMWIMAGEHDR pimage) png_structp state; png_infop pnginfo; png_uint_32 width, height; - int bit_depth, colourtype, i; + int bit_depth, color_type, i; + double file_gamma; + int channels, alpha_present; + png_bytep trans; + int num_trans; + png_color_16p trans_values; GdImageBufferSeekTo(src, 0UL); @@ -71,17 +79,69 @@ GdDecodePNG(buffer_t * src, PMWIMAGEHDR pimage) /* png_init_io(state, src); */ png_set_sig_bytes(state, 8); + png_read_info(state, pnginfo); - png_get_IHDR(state, pnginfo, &width, &height, &bit_depth, &colourtype, + png_get_IHDR(state, pnginfo, &width, &height, &bit_depth, &color_type, NULL, NULL, NULL); - + /* set-up the transformations */ + /* transform paletted images into full-color rgb */ + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_expand (state); + /* expand images to bit-depth 8 (only applicable for grayscale images) */ + if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) + png_set_expand (state); + /* transform transparency maps into full alpha-channel */ + if (png_get_valid (state, pnginfo, PNG_INFO_tRNS)) + png_set_expand (state); + + /* downgrade 16-bit images to 8 bit */ + if (bit_depth == 16) + png_set_strip_16 (state); + /* Handle transparency... */ + if (png_get_valid(state, pnginfo, PNG_INFO_tRNS)) + png_set_tRNS_to_alpha(state); + /* transform grayscale images into full-color */ + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_gray_to_rgb (state); + /* only if file has a file gamma, we do a correction */ + if (png_get_gAMA (state, pnginfo, &file_gamma)) + png_set_gamma (state, (double) 2.2, file_gamma); + + /* all transformations have been registered; now update pnginfo data, + * get rowbytes and channels, and allocate image memory */ + + png_read_update_info (state, pnginfo); + + /* get the new color-type and bit-depth (after expansion/stripping) */ + png_get_IHDR (state, pnginfo, &width, &height, &bit_depth, &color_type, + NULL, NULL, NULL); + + /* calculate new number of channels and store alpha-presence */ + if (color_type == PNG_COLOR_TYPE_GRAY) + channels = 1; + else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + channels = 2; + else if (color_type == PNG_COLOR_TYPE_RGB) + channels = 3; + else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) + channels = 4; + else + channels = 0; /* should never happen */ + alpha_present = (channels - 1) % 2; + +/* old code */ pimage->width = width; pimage->height = height; - pimage->bpp = 24; + pimage->palsize = 0; pimage->planes = 1; - GdComputeImagePitch(pimage->bpp, pimage->width, &pimage->pitch, - &pimage->bytesperpixel); - pimage->compression = MWIMAGE_RGB; + pimage->pitch = width * channels * (bit_depth / 8); + pimage->bpp = channels * 8; + pimage->bytesperpixel = channels; + if (alpha_present) + pimage->compression = MWIMAGE_ALPHA_CHANNEL; /*FIXME - add MWIMAGE_RGB*/ + else + pimage->compression = MWIMAGE_RGB; if(!(pimage->imagebits = malloc(pimage->pitch * pimage->height))) { png_destroy_read_struct(&state, &pnginfo, NULL); goto nomem; @@ -93,17 +153,7 @@ GdDecodePNG(buffer_t * src, PMWIMAGEHDR pimage) for(i = 0; i < pimage->height; i++) rows[i] = pimage->imagebits + (i * pimage->pitch); - png_set_expand(state); - if(bit_depth == 16) - png_set_strip_16(state); - if(colourtype & PNG_COLOR_MASK_ALPHA) - png_set_strip_alpha(state); - if(colourtype == PNG_COLOR_TYPE_GRAY || - colourtype == PNG_COLOR_TYPE_GRAY_ALPHA) - png_set_gray_to_rgb(state); - png_read_image(state, rows); - png_read_end(state, NULL); free(rows); png_destroy_read_struct(&state, &pnginfo, NULL); -- 1.5.1.6