gd_png.c

php-4.4.7学习linux时下载的源代码

			}
			break;

		default:
			/* Palette image, or something coerced to be one */
			for (h = 0; h < height; ++h) {
				for (w = 0; w < width; ++w) {
					register png_byte idx = row_pointers[h][w];
					im->pixels[h][w] = idx;
					open[idx] = 0;
				}
			}
	}
#ifdef DEBUG
	if (!im->trueColor) {
		for (i = num_palette; i < gdMaxColors; ++i) {
			if (!open[i]) {
				php_gd_error("gd-png warning: image data references out-of-range color index (%d)\n", i);
			}
		}
	}
#endif

	if (palette_allocated) {
		gdFree(palette);
	}
	gdFree(image_data);
	gdFree(row_pointers);

	return im;
}

void gdImagePngEx (gdImagePtr im, FILE * outFile, int level)
{
	gdIOCtx *out = gdNewFileCtx(outFile);
	gdImagePngCtxEx(im, out, level);
	out->gd_free(out);
}

void gdImagePng (gdImagePtr im, FILE * outFile)
{
	gdIOCtx *out = gdNewFileCtx(outFile);
  	gdImagePngCtxEx(im, out, -1);
	out->gd_free(out);
}

void * gdImagePngPtr (gdImagePtr im, int *size)
{
	void *rv;
	gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
	gdImagePngCtxEx(im, out, -1);
	rv = gdDPExtractData(out, size);
	out->gd_free(out);

	return rv;
}

void * gdImagePngPtrEx (gdImagePtr im, int *size, int level)
{
	void *rv;
	gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
	gdImagePngCtxEx(im, out, level);
	rv = gdDPExtractData(out, size);
	out->gd_free(out);
	return rv;
}

void gdImagePngCtx (gdImagePtr im, gdIOCtx * outfile)
{
	gdImagePngCtxEx(im, outfile, -1);
}

/* This routine is based in part on code from Dale Lutz (Safe Software Inc.)
 *  and in part on demo code from Chapter 15 of "PNG: The Definitive Guide"
 *  (http://www.cdrom.com/pub/png/pngbook.html).
 */
void gdImagePngCtxEx (gdImagePtr im, gdIOCtx * outfile, int level)
{
	int i, j, bit_depth = 0, interlace_type;
	int width = im->sx;
	int height = im->sy;
	int colors = im->colorsTotal;
	int *open = im->open;
	int mapping[gdMaxColors];	/* mapping[gd_index] == png_index */
	png_byte trans_values[256];
	png_color_16 trans_rgb_value;
	png_color palette[gdMaxColors];
	png_structp png_ptr;
	png_infop info_ptr;
	volatile int transparent = im->transparent;
	volatile int remap = FALSE;

#ifndef PNG_SETJMP_NOT_SUPPORTED
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, &gdPngJmpbufStruct, gdPngErrorHandler, NULL);
#else
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
#endif
	if (png_ptr == NULL) {
		php_gd_error("gd-png error: cannot allocate libpng main struct\n");
		return;
	}

	info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		php_gd_error("gd-png error: cannot allocate libpng info struct\n");
		png_destroy_write_struct (&png_ptr, (png_infopp) NULL);

		return;
    }

#ifndef PNG_SETJMP_NOT_SUPPORTED
	if (setjmp (gdPngJmpbufStruct.jmpbuf)) {
		php_gd_error("gd-png error: setjmp returns error condition\n");
		png_destroy_write_struct (&png_ptr, &info_ptr);

		return;
	}
#endif

	png_set_write_fn(png_ptr, (void *) outfile, gdPngWriteData, gdPngFlushData);

	/* This is best for palette images, and libpng defaults to it for
	 * palette images anyway, so we don't need to do it explicitly.
	 * What to ideally do for truecolor images depends, alas, on the image.
	 * gd is intentionally imperfect and doesn't spend a lot of time
	 * fussing with such things.
	 */
	
	/*  png_set_filter(png_ptr, 0, PNG_FILTER_NONE);  */

	/* 2.0.12: this is finally a parameter */
	png_set_compression_level(png_ptr, level);

	/* can set this to a smaller value without compromising compression if all
	 * image data is 16K or less; will save some decoder memory [min == 8] 
	 */

	/*  png_set_compression_window_bits(png_ptr, 15);  */

	if (!im->trueColor) {
		if (transparent >= im->colorsTotal || (transparent >= 0 && open[transparent])) {
			transparent = -1;
		}

		for (i = 0; i < gdMaxColors; ++i) {
			mapping[i] = -1;
		}

		/* count actual number of colors used (colorsTotal == high-water mark) */
		colors = 0;
		for (i = 0; i < im->colorsTotal; ++i) {
			if (!open[i]) {
				mapping[i] = colors;
				++colors;
			}
		}
		if (colors < im->colorsTotal) {
			remap = TRUE;
		}
		if (colors <= 2) {
			bit_depth = 1;
		} else if (colors <= 4) {
			bit_depth = 2;
		} else if (colors <= 16) { 
			bit_depth = 4;
		} else {
			bit_depth = 8;
		}
	}
	
	interlace_type = im->interlace ? PNG_INTERLACE_ADAM7 : PNG_INTERLACE_NONE;

	if (im->trueColor) {
		if (im->saveAlphaFlag) {
			png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA, interlace_type,
					PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
		} else {
			png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB, interlace_type,
					PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
		}
	} else {
		png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_PALETTE, interlace_type,
			PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
	}

	if (im->trueColor && !im->saveAlphaFlag && (transparent >= 0)) {
		/* 2.0.9: fixed by Thomas Winzig */
		trans_rgb_value.red = gdTrueColorGetRed (im->transparent);
		trans_rgb_value.green = gdTrueColorGetGreen (im->transparent);
		trans_rgb_value.blue = gdTrueColorGetBlue (im->transparent);
		png_set_tRNS(png_ptr, info_ptr, 0, 0, &trans_rgb_value);
	}

	if (!im->trueColor) {
		/* Oy veh. Remap the PNG palette to put the entries with interesting alpha channel
		 * values first. This minimizes the size of the tRNS chunk and thus the size
		 * of the PNG file as a whole. 
		 */
		
		int tc = 0;
		int i;
		int j;
		int k;

		for (i = 0; (i < im->colorsTotal); i++) {
			if ((!im->open[i]) && (im->alpha[i] != gdAlphaOpaque)) {
				tc++;
			}
		}
		if (tc) {
#if 0
			for (i = 0; (i < im->colorsTotal); i++) {
				trans_values[i] = 255 - ((im->alpha[i] << 1) + (im->alpha[i] >> 6));
			}
			png_set_tRNS (png_ptr, info_ptr, trans_values, 256, NULL);
#endif
			if (!remap) {
				remap = TRUE;
			}

			/* (Semi-)transparent indexes come up from the bottom of the list of real colors; opaque
			 * indexes come down from the top
			 */
			j = 0;
			k = colors - 1;

			for (i = 0; i < im->colorsTotal; i++) {
				if (!im->open[i]) {
					if (im->alpha[i] != gdAlphaOpaque) {
						/* Andrew Hull: >> 6, not >> 7! (gd 2.0.5) */ 
						trans_values[j] = 255 - ((im->alpha[i] << 1) + (im->alpha[i] >> 6));
						mapping[i] = j++;
					} else {
						mapping[i] = k--;
					}
				}
			}
			png_set_tRNS(png_ptr, info_ptr, trans_values, tc, NULL);
		}
	}

	/* convert palette to libpng layout */
	if (!im->trueColor) {
		if (remap) {
			for (i = 0; i < im->colorsTotal; ++i) {
				if (mapping[i] < 0) {
					continue;
				}

				palette[mapping[i]].red = im->red[i];
				palette[mapping[i]].green = im->green[i];
				palette[mapping[i]].blue = im->blue[i];
			}
		} else {
			for (i = 0; i < colors; ++i) {
				palette[i].red = im->red[i];
				palette[i].green = im->green[i];
				palette[i].blue = im->blue[i];
			}
		}
		png_set_PLTE(png_ptr, info_ptr, palette, colors);
	}

	/* write out the PNG header info (everything up to first IDAT) */
	png_write_info(png_ptr, info_ptr);

	/* make sure < 8-bit images are packed into pixels as tightly as possible */
	png_set_packing(png_ptr);

	/* This code allocates a set of row buffers and copies the gd image data
	 * into them only in the case that remapping is necessary; in gd 1.3 and
	 * later, the im->pixels array is laid out identically to libpng's row
	 * pointers and can be passed to png_write_image() function directly.
	 * The remapping case could be accomplished with less memory for non-
	 * interlaced images, but interlacing causes some serious complications.
	 */

	if (im->trueColor) {
		/* performance optimizations by Phong Tran */
		int channels = im->saveAlphaFlag ? 4 : 3;
		/* Our little 7-bit alpha channel trick costs us a bit here. */
		png_bytep *row_pointers;
		unsigned char* pOutputRow;
		int **ptpixels = im->tpixels;
		int *pThisRow;
		unsigned char a;
		int thisPixel;
		png_bytep *prow_pointers;
		int saveAlphaFlag = im->saveAlphaFlag;

		row_pointers = safe_emalloc(sizeof(png_bytep), height, 0);
		prow_pointers = row_pointers;
		for (j = 0; j < height; ++j) {
			*prow_pointers = (png_bytep) safe_emalloc(width, channels, 0);
			pOutputRow = *prow_pointers++;
			pThisRow = *ptpixels++;
			for (i = 0; i < width; ++i) {
				thisPixel = *pThisRow++;
				*pOutputRow++ = gdTrueColorGetRed(thisPixel);
				*pOutputRow++ = gdTrueColorGetGreen(thisPixel);
				*pOutputRow++ = gdTrueColorGetBlue(thisPixel);
				if (saveAlphaFlag) {
					/* convert the 7-bit alpha channel to an 8-bit alpha channel.
					 * We do a little bit-flipping magic, repeating the MSB
					 * as the LSB, to ensure that 0 maps to 0 and
					 * 127 maps to 255. We also have to invert to match
					 * PNG's convention in which 255 is opaque.
					 */
					a = gdTrueColorGetAlpha(thisPixel);
					/* Andrew Hull: >> 6, not >> 7! (gd 2.0.5) */ 
					*pOutputRow++ = 255 - ((a << 1) + (a >> 6));
				}
			}
		}

		png_write_image(png_ptr, row_pointers);
		png_write_end(png_ptr, info_ptr);

		for (j = 0; j < height; ++j) {
			gdFree(row_pointers[j]);
		}
	
		gdFree(row_pointers);
	} else {
		if (remap) {
			png_bytep *row_pointers;
			row_pointers = safe_emalloc(sizeof(png_bytep), height, 0);
			for (j = 0; j < height; ++j) {
				row_pointers[j] = (png_bytep) gdMalloc(width);
				for (i = 0; i < width; ++i) {
					row_pointers[j][i] = mapping[im->pixels[j][i]];
				}
			}

			png_write_image(png_ptr, row_pointers);
			png_write_end(png_ptr, info_ptr);

			for (j = 0; j < height; ++j) {
				gdFree(row_pointers[j]);
			}

			gdFree(row_pointers);
		} else {
			png_write_image(png_ptr, im->pixels);
			png_write_end(png_ptr, info_ptr);
		}
	}
	/* 1.6.3: maybe we should give that memory BACK! TBB */
	png_destroy_write_struct(&png_ptr, &info_ptr);
}

#endif /* HAVE_LIBPNG */