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aseprite/src/app/file/png_format.cpp

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// Aseprite
// Copyright (C) 2018 Igara Studio S.A.
// Copyright (C) 2001-2018 David Capello
//
// This program is distributed under the terms of
// the End-User License Agreement for Aseprite.
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "app/app.h"
#include "app/doc.h"
#include "app/file/file.h"
#include "app/file/file_format.h"
#include "app/file/format_options.h"
#include "app/file/png_format.h"
#include "base/file_handle.h"
#include "doc/doc.h"
#include "gfx/color_space.h"
#include <stdio.h>
#include <stdlib.h>
#include "png.h"
namespace app {
using namespace base;
class PngFormat : public FileFormat {
const char* onGetName() const override {
return "png";
}
void onGetExtensions(base::paths& exts) const override {
exts.push_back("png");
}
dio::FileFormat onGetDioFormat() const override {
return dio::FileFormat::PNG_IMAGE;
}
int onGetFlags() const override {
return
FILE_SUPPORT_LOAD |
FILE_SUPPORT_SAVE |
FILE_SUPPORT_RGB |
FILE_SUPPORT_RGBA |
FILE_SUPPORT_GRAY |
FILE_SUPPORT_GRAYA |
FILE_SUPPORT_INDEXED |
FILE_SUPPORT_SEQUENCES |
FILE_SUPPORT_PALETTE_WITH_ALPHA;
}
bool onLoad(FileOp* fop) override;
gfx::ColorSpacePtr loadColorSpace(png_structp png_ptr, png_infop info_ptr);
#ifdef ENABLE_SAVE
bool onSave(FileOp* fop) override;
void saveColorSpace(png_structp png_ptr, png_infop info_ptr, const gfx::ColorSpace* colorSpace);
#endif
};
FileFormat* CreatePngFormat()
{
return new PngFormat;
}
static void report_png_error(png_structp png_ptr, png_const_charp error)
{
((FileOp*)png_get_error_ptr(png_ptr))->setError("libpng: %s\n", error);
}
// TODO this should be information in FileOp parameter of onSave()
static bool fix_one_alpha_pixel = false;
PngEncoderOneAlphaPixel::PngEncoderOneAlphaPixel(bool state)
{
fix_one_alpha_pixel = state;
}
PngEncoderOneAlphaPixel::~PngEncoderOneAlphaPixel()
{
fix_one_alpha_pixel = false;
}
// As in png_fixed_point_to_float() in skia/src/codec/SkPngCodec.cpp
static float png_fixtof(png_fixed_point x)
{
// We multiply by the same factor that libpng used to convert
// fixed point -> double. Since we want floats, we choose to
// do the conversion ourselves rather than convert
// fixed point -> double -> float.
return ((float)x) * 0.00001f;
}
static png_fixed_point png_ftofix(float x)
{
return x * 100000.0f;
}
bool PngFormat::onLoad(FileOp* fop)
{
png_uint_32 width, height, y;
unsigned int sig_read = 0;
png_structp png_ptr;
int bit_depth, color_type, interlace_type;
int num_palette;
png_colorp palette;
png_bytepp rows_pointer;
PixelFormat pixelFormat;
FileHandle handle(open_file_with_exception(fop->filename(), "rb"));
FILE* fp = handle.get();
/* Create and initialize the png_struct with the desired error handler
* functions. If you want to use the default stderr and longjump method,
* you can supply NULL for the last three parameters. We also supply the
* the compiler header file version, so that we know if the application
* was compiled with a compatible version of the library
*/
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)fop,
report_png_error, report_png_error);
if (png_ptr == NULL) {
fop->setError("png_create_read_struct\n");
return false;
}
/* Allocate/initialize the memory for image information. */
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
fop->setError("png_create_info_struct\n");
png_destroy_read_struct(&png_ptr, NULL, NULL);
return false;
}
/* Set error handling if you are using the setjmp/longjmp method (this is
* the normal method of doing things with libpng).
*/
if (setjmp(png_jmpbuf(png_ptr))) {
fop->setError("Error reading PNG file\n");
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}
/* Set up the input control if you are using standard C streams */
png_init_io(png_ptr, fp);
/* If we have already read some of the signature */
png_set_sig_bytes(png_ptr, sig_read);
/* The call to png_read_info() gives us all of the information from the
* PNG file before the first IDAT (image data chunk).
*/
png_read_info(png_ptr, info_ptr);
png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, NULL, NULL);
/* Set up the data transformations you want. Note that these are all
* optional. Only call them if you want/need them. Many of the
* transformations only work on specific types of images, and many
* are mutually exclusive.
*/
/* tell libpng to strip 16 bit/color files down to 8 bits/color */
png_set_strip_16(png_ptr);
/* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
* byte into separate bytes (useful for paletted and grayscale images).
*/
png_set_packing(png_ptr);
/* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
png_set_expand_gray_1_2_4_to_8(png_ptr);
/* Turn on interlace handling. REQUIRED if you are not using
* png_read_image(). To see how to handle interlacing passes,
* see the png_read_row() method below:
*/
int number_passes = png_set_interlace_handling(png_ptr);
/* Optional call to gamma correct and add the background to the palette
* and update info structure.
*/
png_read_update_info(png_ptr, info_ptr);
/* create the output image */
switch (png_get_color_type(png_ptr, info_ptr)) {
case PNG_COLOR_TYPE_RGB_ALPHA:
fop->sequenceSetHasAlpha(true);
case PNG_COLOR_TYPE_RGB:
pixelFormat = IMAGE_RGB;
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
fop->sequenceSetHasAlpha(true);
case PNG_COLOR_TYPE_GRAY:
pixelFormat = IMAGE_GRAYSCALE;
break;
case PNG_COLOR_TYPE_PALETTE:
pixelFormat = IMAGE_INDEXED;
break;
default:
fop->setError("Color type not supported\n)");
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}
int imageWidth = png_get_image_width(png_ptr, info_ptr);
int imageHeight = png_get_image_height(png_ptr, info_ptr);
Image* image = fop->sequenceImage(pixelFormat, imageWidth, imageHeight);
if (!image) {
fop->setError("file_sequence_image %dx%d\n", imageWidth, imageHeight);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}
// Transparent color
png_color_16p png_trans_color = NULL;
// Read the palette
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE &&
png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette)) {
fop->sequenceSetNColors(num_palette);
for (int c=0; c<num_palette; ++c) {
fop->sequenceSetColor(c,
palette[c].red,
palette[c].green,
palette[c].blue);
}
// Read alpha values for palette entries
png_bytep trans = NULL; // Transparent palette entries
int num_trans = 0;
int mask_entry = -1;
png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, nullptr);
for (int i = 0; i < num_trans; ++i) {
fop->sequenceSetAlpha(i, trans[i]);
if (trans[i] < 255) {
fop->sequenceSetHasAlpha(true); // Is a transparent sprite
if (trans[i] == 0) {
if (mask_entry < 0)
mask_entry = i;
}
}
}
if (mask_entry >= 0)
fop->document()->sprite()->setTransparentColor(mask_entry);
}
else {
png_get_tRNS(png_ptr, info_ptr, nullptr, nullptr, &png_trans_color);
}
// Allocate the memory to hold the image using the fields of info_ptr.
rows_pointer = (png_bytepp)png_malloc(png_ptr, sizeof(png_bytep) * height);
for (y = 0; y < height; y++)
rows_pointer[y] = (png_bytep)png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
for (int pass=0; pass<number_passes; ++pass) {
for (y = 0; y < height; y++) {
png_read_rows(png_ptr, rows_pointer+y, nullptr, 1);
fop->setProgress(
(double)((double)pass + (double)(y+1) / (double)(height))
/ (double)number_passes);
if (fop->isStop())
break;
}
}
// Convert rows_pointer into the doc::Image
for (y = 0; y < height; y++) {
// RGB_ALPHA
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB_ALPHA) {
uint8_t* src_address = rows_pointer[y];
uint32_t* dst_address = (uint32_t*)image->getPixelAddress(0, y);
unsigned int x, r, g, b, a;
for (x=0; x<width; x++) {
r = *(src_address++);
g = *(src_address++);
b = *(src_address++);
a = *(src_address++);
*(dst_address++) = rgba(r, g, b, a);
}
}
// RGB
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB) {
uint8_t* src_address = rows_pointer[y];
uint32_t* dst_address = (uint32_t*)image->getPixelAddress(0, y);
unsigned int x, r, g, b, a;
for (x=0; x<width; x++) {
r = *(src_address++);
g = *(src_address++);
b = *(src_address++);
// Transparent color
if (png_trans_color &&
r == png_trans_color->red &&
g == png_trans_color->green &&
b == png_trans_color->blue) {
a = 0;
if (!fop->sequenceGetHasAlpha())
fop->sequenceSetHasAlpha(true);
}
else
a = 255;
*(dst_address++) = rgba(r, g, b, a);
}
}
// GRAY_ALPHA
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY_ALPHA) {
uint8_t* src_address = rows_pointer[y];
uint16_t* dst_address = (uint16_t*)image->getPixelAddress(0, y);
unsigned int x, k, a;
for (x=0; x<width; x++) {
k = *(src_address++);
a = *(src_address++);
*(dst_address++) = graya(k, a);
}
}
// GRAY
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY) {
uint8_t* src_address = rows_pointer[y];
uint16_t* dst_address = (uint16_t*)image->getPixelAddress(0, y);
unsigned int x, k, a;
for (x=0; x<width; x++) {
k = *(src_address++);
// Transparent color
if (png_trans_color &&
k == png_trans_color->gray) {
a = 0;
if (!fop->sequenceGetHasAlpha())
fop->sequenceSetHasAlpha(true);
}
else
a = 255;
*(dst_address++) = graya(k, a);
}
}
// PALETTE
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE) {
uint8_t* src_address = rows_pointer[y];
uint8_t* dst_address = (uint8_t*)image->getPixelAddress(0, y);
unsigned int x;
for (x=0; x<width; x++)
*(dst_address++) = *(src_address++);
}
png_free(png_ptr, rows_pointer[y]);
}
png_free(png_ptr, rows_pointer);
// Setup the color space.
auto colorSpace = PngFormat::loadColorSpace(png_ptr, info_ptr);
if (colorSpace)
fop->setEmbeddedColorProfile();
else { // sRGB is the default PNG color space.
colorSpace = gfx::ColorSpace::MakeSRGB();
}
if (colorSpace &&
fop->document()->sprite()->colorSpace()->type() == gfx::ColorSpace::None) {
fop->document()->sprite()->setColorSpace(colorSpace);
fop->document()->notifyColorSpaceChanged();
}
// Clean up after the read, and free any memory allocated
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return true;
}
// Returns a colorSpace object that represents any
// color space information in the encoded data. If the encoded data
// contains an invalid/unsupported color space, this will return
// NULL. If there is no color space information, it will guess sRGB
//
// Code to read color spaces from png files from Skia (SkPngCodec.cpp)
// by Google Inc.
gfx::ColorSpacePtr PngFormat::loadColorSpace(png_structp png_ptr, png_infop info_ptr)
{
// First check for an ICC profile
png_bytep profile;
png_uint_32 length;
// The below variables are unused, however, we need to pass them in anyway or
// png_get_iCCP() will return nothing.
// Could knowing the |name| of the profile ever be interesting? Maybe for debugging?
png_charp name;
// The |compression| is uninteresting since:
// (1) libpng has already decompressed the profile for us.
// (2) "deflate" is the only mode of decompression that libpng supports.
int compression;
if (PNG_INFO_iCCP == png_get_iCCP(png_ptr, info_ptr,
&name, &compression,
&profile, &length)) {
auto colorSpace = gfx::ColorSpace::MakeICC(profile, length);
if (name)
colorSpace->setName(name);
return colorSpace;
}
// Second, check for sRGB.
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) {
// sRGB chunks also store a rendering intent: Absolute, Relative,
// Perceptual, and Saturation.
return gfx::ColorSpace::MakeSRGB();
}
// Next, check for chromaticities.
png_fixed_point wx, wy, rx, ry, gx, gy, bx, by, invGamma;
if (png_get_cHRM_fixed(png_ptr, info_ptr,
&wx, &wy, &rx, &ry, &gx, &gy, &bx, &by)) {
gfx::ColorSpacePrimaries primaries;
primaries.wx = png_fixtof(wx); primaries.wy = png_fixtof(wy);
primaries.rx = png_fixtof(rx); primaries.ry = png_fixtof(ry);
primaries.gx = png_fixtof(gx); primaries.gy = png_fixtof(gy);
primaries.bx = png_fixtof(bx); primaries.by = png_fixtof(by);
if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &invGamma)) {
gfx::ColorSpaceTransferFn fn;
fn.a = 1.0f;
fn.b = fn.c = fn.d = fn.e = fn.f = 0.0f;
fn.g = 1.0f / png_fixtof(invGamma);
return gfx::ColorSpace::MakeRGB(fn, primaries);
}
// Default to sRGB gamma if the image has color space information,
// but does not specify gamma.
return gfx::ColorSpace::MakeRGBWithSRGBGamma(primaries);
}
// Last, check for gamma.
if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &invGamma)) {
// Since there is no cHRM, we will guess sRGB gamut.
return gfx::ColorSpace::MakeSRGBWithGamma(1.0f / png_fixtof(invGamma));
}
// No color space.
return nullptr;
}
#ifdef ENABLE_SAVE
bool PngFormat::onSave(FileOp* fop)
{
png_structp png_ptr;
png_infop info_ptr;
png_colorp palette = nullptr;
png_bytep row_pointer;
int color_type = 0;
FileHandle handle(open_file_with_exception_sync_on_close(fop->filename(), "wb"));
FILE* fp = handle.get();
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp)fop,
report_png_error, report_png_error);
if (png_ptr == NULL) {
return false;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
png_destroy_write_struct(&png_ptr, NULL);
return false;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return false;
}
png_init_io(png_ptr, fp);
const Image* image = fop->sequenceImage();
switch (image->pixelFormat()) {
case IMAGE_RGB:
color_type =
(fop->document()->sprite()->needAlpha() ||
fix_one_alpha_pixel ?
PNG_COLOR_TYPE_RGB_ALPHA:
PNG_COLOR_TYPE_RGB);
break;
case IMAGE_GRAYSCALE:
color_type =
(fop->document()->sprite()->needAlpha() ||
fix_one_alpha_pixel ?
PNG_COLOR_TYPE_GRAY_ALPHA:
PNG_COLOR_TYPE_GRAY);
break;
case IMAGE_INDEXED:
if (fix_one_alpha_pixel)
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
else
color_type = PNG_COLOR_TYPE_PALETTE;
break;
}
const png_uint_32 width = image->width();
const png_uint_32 height = image->height();
png_set_IHDR(png_ptr, info_ptr, width, height, 8, color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
if (fop->preserveColorProfile() &&
fop->document()->sprite()->colorSpace())
saveColorSpace(png_ptr, info_ptr, fop->document()->sprite()->colorSpace().get());
if (color_type == PNG_COLOR_TYPE_PALETTE) {
int c, r, g, b;
int pal_size = fop->sequenceGetNColors();
pal_size = MID(1, pal_size, PNG_MAX_PALETTE_LENGTH);
#if PNG_MAX_PALETTE_LENGTH != 256
#error PNG_MAX_PALETTE_LENGTH should be 256
#endif
// Save the color palette.
palette = (png_colorp)png_malloc(png_ptr, pal_size * sizeof(png_color));
for (c = 0; c < pal_size; c++) {
fop->sequenceGetColor(c, &r, &g, &b);
palette[c].red = r;
palette[c].green = g;
palette[c].blue = b;
}
png_set_PLTE(png_ptr, info_ptr, palette, pal_size);
// If the sprite does not have a (visible) background layer, we
// put alpha=0 to the transparent color.
int mask_entry = -1;
if (fop->document()->sprite()->backgroundLayer() == NULL ||
!fop->document()->sprite()->backgroundLayer()->isVisible()) {
mask_entry = fop->document()->sprite()->transparentColor();
}
bool all_opaque = true;
int num_trans = pal_size;
png_bytep trans = (png_bytep)png_malloc(png_ptr, num_trans);
for (c=0; c<num_trans; ++c) {
int alpha = 255;
fop->sequenceGetAlpha(c, &alpha);
trans[c] = (c == mask_entry ? 0: alpha);
if (alpha < 255)
all_opaque = false;
}
if (!all_opaque || mask_entry >= 0)
png_set_tRNS(png_ptr, info_ptr, trans, num_trans, nullptr);
png_free(png_ptr, trans);
}
png_write_info(png_ptr, info_ptr);
png_set_packing(png_ptr);
row_pointer = (png_bytep)png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
for (png_uint_32 y=0; y<height; ++y) {
uint8_t* dst_address = row_pointer;
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB_ALPHA) {
unsigned int x, c, a;
bool opaque = true;
if (image->pixelFormat() == IMAGE_RGB) {
uint32_t* src_address = (uint32_t*)image->getPixelAddress(0, y);
for (x=0; x<width; ++x) {
c = *(src_address++);
a = rgba_geta(c);
if (opaque) {
if (a < 255)
opaque = false;
else if (fix_one_alpha_pixel && x == width-1 && y == height-1)
a = 254;
}
*(dst_address++) = rgba_getr(c);
*(dst_address++) = rgba_getg(c);
*(dst_address++) = rgba_getb(c);
*(dst_address++) = a;
}
}
// In case that we are converting an indexed image to RGB just
// to convert one pixel with alpha=254.
else if (image->pixelFormat() == IMAGE_INDEXED) {
uint8_t* src_address = (uint8_t*)image->getPixelAddress(0, y);
unsigned int x, c;
int r, g, b, a;
bool opaque = true;
for (x=0; x<width; ++x) {
c = *(src_address++);
fop->sequenceGetColor(c, &r, &g, &b);
fop->sequenceGetAlpha(c, &a);
if (opaque) {
if (a < 255)
opaque = false;
else if (fix_one_alpha_pixel && x == width-1 && y == height-1)
a = 254;
}
*(dst_address++) = r;
*(dst_address++) = g;
*(dst_address++) = b;
*(dst_address++) = a;
}
}
}
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB) {
uint32_t* src_address = (uint32_t*)image->getPixelAddress(0, y);
unsigned int x, c;
for (x=0; x<width; ++x) {
c = *(src_address++);
*(dst_address++) = rgba_getr(c);
*(dst_address++) = rgba_getg(c);
*(dst_address++) = rgba_getb(c);
}
}
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY_ALPHA) {
uint16_t* src_address = (uint16_t*)image->getPixelAddress(0, y);
unsigned int x, c, a;
bool opaque = true;
for (x=0; x<width; x++) {
c = *(src_address++);
a = graya_geta(c);
if (opaque) {
if (a < 255)
opaque = false;
else if (fix_one_alpha_pixel && x == width-1 && y == height-1)
a = 254;
}
*(dst_address++) = graya_getv(c);
*(dst_address++) = a;
}
}
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY) {
uint16_t* src_address = (uint16_t*)image->getPixelAddress(0, y);
unsigned int x, c;
for (x=0; x<width; ++x) {
c = *(src_address++);
*(dst_address++) = graya_getv(c);
}
}
else if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE) {
uint8_t* src_address = (uint8_t*)image->getPixelAddress(0, y);
unsigned int x;
for (x=0; x<width; ++x)
*(dst_address++) = *(src_address++);
}
png_write_rows(png_ptr, &row_pointer, 1);
fop->setProgress((double)(y+1) / (double)(height));
}
png_free(png_ptr, row_pointer);
png_write_end(png_ptr, info_ptr);
if (image->pixelFormat() == IMAGE_INDEXED) {
png_free(png_ptr, palette);
palette = nullptr;
}
png_destroy_write_struct(&png_ptr, &info_ptr);
return true;
}
void PngFormat::saveColorSpace(png_structp png_ptr, png_infop info_ptr,
const gfx::ColorSpace* colorSpace)
{
switch (colorSpace->type()) {
case gfx::ColorSpace::None:
// Do just nothing (png file without profile, like old Aseprite versions)
break;
case gfx::ColorSpace::sRGB:
// TODO save the original intent
if (!colorSpace->hasGamma()) {
png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
return;
}
// Continue to RGB case...
case gfx::ColorSpace::RGB: {
if (colorSpace->hasPrimaries()) {
const gfx::ColorSpacePrimaries* p = colorSpace->primaries();
png_set_cHRM_fixed(png_ptr, info_ptr,
png_ftofix(p->wx), png_ftofix(p->wy),
png_ftofix(p->rx), png_ftofix(p->ry),
png_ftofix(p->gx), png_ftofix(p->gy),
png_ftofix(p->bx), png_ftofix(p->by));
}
if (colorSpace->hasGamma()) {
png_set_gAMA_fixed(png_ptr, info_ptr,
png_ftofix(1.0f / colorSpace->gamma()));
}
break;
}
case gfx::ColorSpace::ICC: {
png_set_iCCP(png_ptr, info_ptr,
(png_const_charp)colorSpace->name().c_str(),
PNG_COMPRESSION_TYPE_DEFAULT,
(png_const_bytep)colorSpace->iccData(),
(png_uint_32)colorSpace->iccSize());
break;
}
}
}
#endif // ENABLE_SAVE
} // namespace app
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