static FIBITMAP * DLL_CALLCONV
Load(FreeImageIO *io, fi_handle handle, int page, int flags, void *data) {
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
png_uint_32 width, height;
int color_type;
int bit_depth;
int pixel_depth = 0; // pixel_depth = bit_depth * channels
FIBITMAP *dib = NULL;
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
int res_unit_type = PNG_RESOLUTION_UNKNOWN;
png_get_pHYs(png_ptr,info_ptr, &res_x, &res_y, &res_unit_type);
if (res_unit_type == PNG_RESOLUTION_METER) {
FreeImage_SetDotsPerMeterX(dib, res_x);
FreeImage_SetDotsPerMeterY(dib, res_y);
}
}
// get possible ICC profile
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
png_charp profile_name = NULL;
png_bytep profile_data = NULL;
png_uint_32 profile_length = 0;
int compression_type;
png_get_iCCP(png_ptr, info_ptr, &profile_name, &compression_type, &profile_data, &profile_length);
// copy ICC profile data (must be done after FreeImage_AllocateHeader)
FreeImage_CreateICCProfile(dib, profile_data, profile_length);
}
// --- header only mode => clean-up and return
if (header_only) {
// get possible metadata (it can be located both before and after the image data)
ReadMetadata(png_ptr, info_ptr, dib);
if (png_ptr) {
// clean up after the read, and free any memory allocated - REQUIRED
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
return dib;
}
// set the individual row_pointers to point at the correct offsets
row_pointers = (png_bytepp)malloc(height * sizeof(png_bytep));
if (!row_pointers) {
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
FreeImage_Unload(dib);
return NULL;
}
// read in the bitmap bits via the pointer table
// allow loading of PNG with minor errors (such as images with several IDAT chunks)
for (png_uint_32 k = 0; k < height; k++) {
row_pointers[height - 1 - k] = FreeImage_GetScanLine(dib, k);
}
png_set_benign_errors(png_ptr, 1);
png_read_image(png_ptr, row_pointers);
// check if the bitmap contains transparency, if so enable it in the header
if (FreeImage_GetBPP(dib) == 32) {
if (FreeImage_GetColorType(dib) == FIC_RGBALPHA) {
FreeImage_SetTransparent(dib, TRUE);
} else {
FreeImage_SetTransparent(dib, FALSE);
}
}
// cleanup
if (row_pointers) {
free(row_pointers);
row_pointers = NULL;
}
// read the rest of the file, getting any additional chunks in info_ptr
png_read_end(png_ptr, info_ptr);
// get possible metadata (it can be located both before and after the image data)
ReadMetadata(png_ptr, info_ptr, dib);
if (png_ptr) {
// clean up after the read, and free any memory allocated - REQUIRED
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
return dib;
} catch (const char *text) {
if (png_ptr) {
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
if (row_pointers) {
free(row_pointers);
}
if (dib) {
FreeImage_Unload(dib);
}
FreeImage_OutputMessageProc(s_format_id, text);
return NULL;
}
}
return NULL;
}
static FIBITMAP * DLL_CALLCONV
Load(FreeImageIO *io, fi_handle handle, int page, int flags, void *data) {
png_structp png_ptr = NULL;
png_infop info_ptr;
png_uint_32 width, height;
png_colorp png_palette = NULL;
int color_type, palette_entries = 0;
int bit_depth, pixel_depth; // pixel_depth = bit_depth * channels
FIBITMAP *dib = NULL;
RGBQUAD *palette = NULL; // pointer to dib palette
png_bytepp row_pointers = NULL;
int i;
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);
pixel_depth = png_get_bit_depth(png_ptr, info_ptr) * png_get_channels(png_ptr, info_ptr);
// get image data type (assume standard image type)
FREE_IMAGE_TYPE image_type = FIT_BITMAP;
if (bit_depth == 16) {
if ((pixel_depth == 16) && (color_type == PNG_COLOR_TYPE_GRAY)) {
image_type = FIT_UINT16;
}
else if ((pixel_depth == 48) && (color_type == PNG_COLOR_TYPE_RGB)) {
image_type = FIT_RGB16;
}
else if ((pixel_depth == 64) && (color_type == PNG_COLOR_TYPE_RGB_ALPHA)) {
image_type = FIT_RGBA16;
} else {
// tell libpng to strip 16 bit/color files down to 8 bits/color
png_set_strip_16(png_ptr);
bit_depth = 8;
}
}
#ifndef FREEIMAGE_BIGENDIAN
if((image_type == FIT_UINT16) || (image_type == FIT_RGB16) || (image_type == FIT_RGBA16)) {
// turn on 16 bit byte swapping
png_set_swap(png_ptr);
}
#endif
// set some additional flags
switch(color_type) {
case PNG_COLOR_TYPE_RGB:
case PNG_COLOR_TYPE_RGB_ALPHA:
#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
// flip the RGB pixels to BGR (or RGBA to BGRA)
if(image_type == FIT_BITMAP) {
png_set_bgr(png_ptr);
}
#endif
break;
case PNG_COLOR_TYPE_PALETTE:
// expand palette images to the full 8 bits from 2 bits/pixel
if (pixel_depth == 2) {
png_set_packing(png_ptr);
pixel_depth = 8;
}
break;
case PNG_COLOR_TYPE_GRAY:
// expand grayscale images to the full 8 bits from 2 bits/pixel
// but *do not* expand fully transparent palette entries to a full alpha channel
if (pixel_depth == 2) {
png_set_expand_gray_1_2_4_to_8(png_ptr);
pixel_depth = 8;
}
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
// expand 8-bit greyscale + 8-bit alpha to 32-bit
png_set_gray_to_rgb(png_ptr);
#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
// flip the RGBA pixels to BGRA
png_set_bgr(png_ptr);
#endif
pixel_depth = 32;
break;
default:
throw FI_MSG_ERROR_UNSUPPORTED_FORMAT;
}
// unlike the example in the libpng documentation, we have *no* idea where
// this file may have come from--so if it doesn't have a file gamma, don't
// do any correction ("do no harm")
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA)) {
double gamma = 0;
double screen_gamma = 2.2;
if (png_get_gAMA(png_ptr, info_ptr, &gamma) && ( flags & PNG_IGNOREGAMMA ) != PNG_IGNOREGAMMA) {
png_set_gamma(png_ptr, screen_gamma, gamma);
}
}
// all transformations have been registered; now update info_ptr data
png_read_update_info(png_ptr, info_ptr);
// color type may have changed, due to our transformations
color_type = png_get_color_type(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:
png_set_invert_alpha(png_ptr);
if(image_type == FIT_BITMAP) {
dib = FreeImage_AllocateHeader(header_only, width, height, 24, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
} else {
dib = FreeImage_AllocateHeaderT(header_only, image_type, width, height, pixel_depth);
}
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
if(image_type == FIT_BITMAP) {
dib = FreeImage_AllocateHeader(header_only, width, height, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
} else {
dib = FreeImage_AllocateHeaderT(header_only, image_type, width, height, pixel_depth);
}
break;
case PNG_COLOR_TYPE_PALETTE:
dib = FreeImage_AllocateHeader(header_only, width, height, pixel_depth);
png_get_PLTE(png_ptr,info_ptr, &png_palette, &palette_entries);
palette_entries = MIN((unsigned)palette_entries, FreeImage_GetColorsUsed(dib));
palette = FreeImage_GetPalette(dib);
// store the palette
for (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);
if(pixel_depth <= 8) {
palette = FreeImage_GetPalette(dib);
palette_entries = 1 << pixel_depth;
for (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;
}
// 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 < palette_entries) {
BYTE table[256];
memset(table, 0xFF, palette_entries);
table[trans_color->gray] = 0;
FreeImage_SetTransparencyTable(dib, table, palette_entries);
}
} else if((color_type == PNG_COLOR_TYPE_PALETTE) && trans_alpha) {
// transparency table
FreeImage_SetTransparencyTable(dib, (BYTE *)trans_alpha, num_trans);
}
}
// store the background color
if (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
int res_unit_type = PNG_RESOLUTION_UNKNOWN;
png_get_pHYs(png_ptr,info_ptr, &res_x, &res_y, &res_unit_type);
if (res_unit_type == PNG_RESOLUTION_METER) {
FreeImage_SetDotsPerMeterX(dib, res_x);
FreeImage_SetDotsPerMeterY(dib, res_y);
}
}
// get possible ICC profile
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
png_charp profile_name = NULL;
png_bytep profile_data = NULL;
png_uint_32 profile_length = 0;
int compression_type;
png_get_iCCP(png_ptr, info_ptr, &profile_name, &compression_type, &profile_data, &profile_length);
// copy ICC profile data (must be done after FreeImage_AllocateHeader)
FreeImage_CreateICCProfile(dib, profile_data, profile_length);
}
// --- header only mode => clean-up and return
if (header_only) {
// get possible metadata (it can be located both before and after the image data)
ReadMetadata(png_ptr, info_ptr, dib);
if (png_ptr) {
// clean up after the read, and free any memory allocated - REQUIRED
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
return dib;
}
// set the individual row_pointers to point at the correct offsets
row_pointers = (png_bytepp)malloc(height * sizeof(png_bytep));
if (!row_pointers) {
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
FreeImage_Unload(dib);
return NULL;
}
// read in the bitmap bits via the pointer table
// allow loading of PNG with minor errors (such as images with several IDAT chunks)
for (png_uint_32 k = 0; k < height; k++) {
row_pointers[height - 1 - k] = FreeImage_GetScanLine(dib, k);
}
png_set_benign_errors(png_ptr, 1);
png_read_image(png_ptr, row_pointers);
// check if the bitmap contains transparency, if so enable it in the header
if (FreeImage_GetBPP(dib) == 32) {
if (FreeImage_GetColorType(dib) == FIC_RGBALPHA) {
FreeImage_SetTransparent(dib, TRUE);
} else {
FreeImage_SetTransparent(dib, FALSE);
}
}
// cleanup
if (row_pointers) {
free(row_pointers);
row_pointers = NULL;
}
// read the rest of the file, getting any additional chunks in info_ptr
png_read_end(png_ptr, info_ptr);
// get possible metadata (it can be located both before and after the image data)
ReadMetadata(png_ptr, info_ptr, dib);
if (png_ptr) {
// clean up after the read, and free any memory allocated - REQUIRED
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
return dib;
} catch (const char *text) {
if (png_ptr) {
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
}
if (row_pointers) {
free(row_pointers);
}
if (dib) {
FreeImage_Unload(dib);
}
FreeImage_OutputMessageProc(s_format_id, text);
return NULL;
}
}
return NULL;
}
static int /* 0 on success, else an error code */
write_png(const char **name, FILE *fp, int color_type, int bit_depth,
volatile png_fixed_point gamma,
unsigned int filters, unsigned int *colors)
{
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, name, makepng_error, makepng_warning);
volatile png_infop info_ptr = NULL;
volatile png_bytep row = NULL;
if (png_ptr == NULL) {
fprintf(stderr, "makepng: OOM allocating write structure\n");
return 1;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_structp nv_ptr = png_ptr;
png_infop nv_info = info_ptr;
png_ptr = NULL;
info_ptr = NULL;
png_destroy_write_struct(&nv_ptr, &nv_info);
if (row != NULL) free(row);
return 1;
}
/* Allow benign errors so that we can write PNGs with errors */
png_set_benign_errors(png_ptr, 1/*allowed*/);
png_init_io(png_ptr, fp);
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) png_error(png_ptr, "OOM allocating info structure");
unsigned int size = 500;
unsigned int i;
png_set_IHDR(png_ptr, info_ptr, size, size, bit_depth, color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
if (gamma == PNG_DEFAULT_sRGB) png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
/* Write the file header. */
png_write_info(png_ptr, info_ptr);
/* Restrict the filters */
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, filters);
int passes = png_set_interlace_handling(png_ptr);
int pass;
png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
row = malloc(rowbytes);
if (row == NULL) png_error(png_ptr, "OOM allocating row buffer");
for (pass = 0; pass < passes; ++pass) {
unsigned int y;
for (y=0; y<size; ++y) {
generate_row(row, rowbytes, y, color_type, bit_depth);
png_write_row(png_ptr, row);
}
}
/* Finish writing the file. */
png_write_end(png_ptr, info_ptr);
png_structp nv_ptr = png_ptr;
png_infop nv_info = info_ptr;
png_ptr = NULL;
info_ptr = NULL;
png_destroy_write_struct(&nv_ptr, &nv_info);
free(row);
return 0;
}
