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src/Source/FreeImage/PluginPNG.cpp  view on Meta::CPAN

// PNG Loader and Writer
//
// Design and implementation by
// - Floris van den Berg (flvdberg@wxs.nl)
// - Herve Drolon (drolon@infonie.fr)
// - Detlev Vendt (detlev.vendt@brillit.de)
// - Aaron Shumate (trek@startreker.com)
// - Tanner Helland (tannerhelland@users.sf.net)
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================

#ifdef _MSC_VER 
#pragma warning (disable : 4786) // identifier was truncated to 'number' characters
#endif

#include "FreeImage.h"
#include "Utilities.h"

#include "../Metadata/FreeImageTag.h"

// ----------------------------------------------------------

#define PNG_BYTES_TO_CHECK 8

#undef PNG_Z_DEFAULT_COMPRESSION	// already used in ../LibPNG/pnglibconf.h

// ----------------------------------------------------------

#include "../ZLib/zlib.h"
#include "../LibPNG/png.h"

// ----------------------------------------------------------

typedef struct {
    FreeImageIO *s_io;
    fi_handle    s_handle;
} fi_ioStructure, *pfi_ioStructure;

// ==========================================================
// libpng interface
// ==========================================================

static void
_ReadProc(png_structp png_ptr, unsigned char *data, png_size_t size) {
    pfi_ioStructure pfio = (pfi_ioStructure)png_get_io_ptr(png_ptr);
	unsigned n = pfio->s_io->read_proc(data, (unsigned int)size, 1, pfio->s_handle);
	if(size && (n == 0)) {
		throw "Read error: invalid or corrupted PNG file";
	}
}

static void
_WriteProc(png_structp png_ptr, unsigned char *data, png_size_t size) {
    pfi_ioStructure pfio = (pfi_ioStructure)png_get_io_ptr(png_ptr);
    pfio->s_io->write_proc(data, (unsigned int)size, 1, pfio->s_handle);
}

static void
_FlushProc(png_structp png_ptr) {
	(png_structp)png_ptr;
	// empty flush implementation
}

static void
error_handler(png_structp png_ptr, const char *error) {
	(png_structp)png_ptr;
	throw error;
}

// in FreeImage warnings disabled

static void
warning_handler(png_structp png_ptr, const char *warning) {
	(png_structp)png_ptr;
	(char*)warning;
}

// ==========================================================
// Metadata routines
// ==========================================================

static BOOL 
ReadMetadata(png_structp png_ptr, png_infop info_ptr, FIBITMAP *dib) {
	// XMP keyword
	const char *g_png_xmp_keyword = "XML:com.adobe.xmp";

	FITAG *tag = NULL;
	png_textp text_ptr = NULL;
	png_timep mod_time = NULL;
	int num_text = 0;

	// iTXt/tEXt/zTXt chuncks
	if(png_get_text(png_ptr, info_ptr, &text_ptr, &num_text) > 0) {
		for(int i = 0; i < num_text; i++) {
			// create a tag
			tag = FreeImage_CreateTag();
			if(!tag) return FALSE;

			DWORD tag_length = (DWORD) MAX(text_ptr[i].text_length, text_ptr[i].itxt_length);

			FreeImage_SetTagLength(tag, tag_length);
			FreeImage_SetTagCount(tag, tag_length);
			FreeImage_SetTagType(tag, FIDT_ASCII);
			FreeImage_SetTagValue(tag, text_ptr[i].text);

			if(strcmp(text_ptr[i].key, g_png_xmp_keyword) == 0) {
				// store the tag as XMP
				FreeImage_SetTagKey(tag, g_TagLib_XMPFieldName);
				FreeImage_SetMetadata(FIMD_XMP, dib, FreeImage_GetTagKey(tag), tag);
			} else {
				// store the tag as a comment
				FreeImage_SetTagKey(tag, text_ptr[i].key);
				FreeImage_SetMetadata(FIMD_COMMENTS, dib, FreeImage_GetTagKey(tag), tag);
			}
			
			// destroy the tag
			FreeImage_DeleteTag(tag);
		}
	}

	// timestamp chunk
	if(png_get_tIME(png_ptr, info_ptr, &mod_time)) {
		char timestamp[32];
		// create a tag
		tag = FreeImage_CreateTag();
		if(!tag) return FALSE;

src/Source/FreeImage/PluginPNG.cpp  view on Meta::CPAN

	png_bytepp row_pointers = NULL;

    fi_ioStructure fio;
    fio.s_handle = handle;
	fio.s_io = io;
    
	if (handle) {
		BOOL header_only = (flags & FIF_LOAD_NOPIXELS) == FIF_LOAD_NOPIXELS;

		try {		
			// check to see if the file is in fact a PNG file

			BYTE png_check[PNG_BYTES_TO_CHECK];

			io->read_proc(png_check, PNG_BYTES_TO_CHECK, 1, handle);

			if (png_sig_cmp(png_check, (png_size_t)0, PNG_BYTES_TO_CHECK) != 0) {
				return NULL;	// Bad signature
			}
			
			// create the chunk manage structure

			png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, error_handler, warning_handler);

			if (!png_ptr) {
				return NULL;			
			}

			// create the info structure

		    info_ptr = png_create_info_struct(png_ptr);

			if (!info_ptr) {
				png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
				return NULL;
			}

			// init the IO

			png_set_read_fn(png_ptr, &fio, _ReadProc);

            if (setjmp(png_jmpbuf(png_ptr))) {
				png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
				return NULL;
			}

			// because we have already read the signature...

			png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK);

			// read the IHDR chunk

			png_read_info(png_ptr, info_ptr);
			png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, NULL, NULL, NULL);

			// configure the decoder

			FREE_IMAGE_TYPE image_type = FIT_BITMAP;

			if(!ConfigureDecoder(png_ptr, info_ptr, flags, &image_type)) {
				throw FI_MSG_ERROR_UNSUPPORTED_FORMAT;
			}

			// update image info

			color_type = png_get_color_type(png_ptr, info_ptr);
			bit_depth = png_get_bit_depth(png_ptr, info_ptr);
			pixel_depth = bit_depth * png_get_channels(png_ptr, info_ptr);

			// create a dib and write the bitmap header
			// set up the dib palette, if needed

			switch (color_type) {
				case PNG_COLOR_TYPE_RGB:
				case PNG_COLOR_TYPE_RGB_ALPHA:
					dib = FreeImage_AllocateHeaderT(header_only, image_type, width, height, pixel_depth, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					break;

				case PNG_COLOR_TYPE_PALETTE:
					dib = FreeImage_AllocateHeaderT(header_only, image_type, width, height, pixel_depth, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					if(dib) {
						png_colorp png_palette = NULL;
						int palette_entries = 0;

						png_get_PLTE(png_ptr,info_ptr, &png_palette, &palette_entries);

						palette_entries = MIN((unsigned)palette_entries, FreeImage_GetColorsUsed(dib));

						// store the palette

						RGBQUAD *palette = FreeImage_GetPalette(dib);
						for(int i = 0; i < palette_entries; i++) {
							palette[i].rgbRed   = png_palette[i].red;
							palette[i].rgbGreen = png_palette[i].green;
							palette[i].rgbBlue  = png_palette[i].blue;
						}
					}
					break;

				case PNG_COLOR_TYPE_GRAY:
					dib = FreeImage_AllocateHeaderT(header_only, image_type, width, height, pixel_depth, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);

					if(dib && (pixel_depth <= 8)) {
						RGBQUAD *palette = FreeImage_GetPalette(dib);
						const int palette_entries = 1 << pixel_depth;

						for(int i = 0; i < palette_entries; i++) {
							palette[i].rgbRed   =
							palette[i].rgbGreen =
							palette[i].rgbBlue  = (BYTE)((i * 255) / (palette_entries - 1));
						}
					}
					break;

				default:
					throw FI_MSG_ERROR_UNSUPPORTED_FORMAT;
			}

			if(!dib) {
				throw FI_MSG_ERROR_DIB_MEMORY;
			}

			// store the transparency table

			if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
				// array of alpha (transparency) entries for palette
				png_bytep trans_alpha = NULL;
				// number of transparent entries
				int num_trans = 0;						
				// graylevel or color sample values of the single transparent color for non-paletted images
				png_color_16p trans_color = NULL;

				png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans, &trans_color);

				if((color_type == PNG_COLOR_TYPE_GRAY) && trans_color) {
					// single transparent color
					if (trans_color->gray < 256) { 
						BYTE table[256]; 
						memset(table, 0xFF, 256); 
						table[trans_color->gray] = 0; 
						FreeImage_SetTransparencyTable(dib, table, 256); 
					}
					// check for a full transparency table, too
					else if ((trans_alpha) && (pixel_depth <= 8)) {
						FreeImage_SetTransparencyTable(dib, (BYTE *)trans_alpha, num_trans);
					}

				} else if((color_type == PNG_COLOR_TYPE_PALETTE) && trans_alpha) {
					// transparency table
					FreeImage_SetTransparencyTable(dib, (BYTE *)trans_alpha, num_trans);
				}
			}

			// store the background color (only supported for FIT_BITMAP types)

			if ((image_type == FIT_BITMAP) && png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD)) {
				// Get the background color to draw transparent and alpha images over.
				// Note that even if the PNG file supplies a background, you are not required to
				// use it - you should use the (solid) application background if it has one.

				png_color_16p image_background = NULL;
				RGBQUAD rgbBkColor;

				if (png_get_bKGD(png_ptr, info_ptr, &image_background)) {
					rgbBkColor.rgbRed      = (BYTE)image_background->red;
					rgbBkColor.rgbGreen    = (BYTE)image_background->green;
					rgbBkColor.rgbBlue     = (BYTE)image_background->blue;
					rgbBkColor.rgbReserved = 0;

					FreeImage_SetBackgroundColor(dib, &rgbBkColor);
				}
			}

			// get physical resolution

			if (png_get_valid(png_ptr, info_ptr, PNG_INFO_pHYs)) {
				png_uint_32 res_x, res_y;
				
				// we'll overload this var and use 0 to mean no phys data,
				// since if it's not in meters we can't use it anyway