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Minor changes/comments to new gif encoder

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This commit is contained in:
David Capello 2020-03-26 16:19:48 -03:00
parent 7ed83c10cc
commit b007c4dd0e
6 changed files with 204 additions and 115 deletions
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270
src/app/file/gif_format.cpp
View File

@ -891,6 +891,34 @@ bool GifFormat::onLoad(FileOp* fop)
#ifdef ENABLE_SAVE
// Our stragegy to encode GIF files depends of the sprite color mode:
//
// 1) If the sprite is indexed, we have two paths:
// * For opaque an opaque sprite we can save it as it is (with the
// same indexes/pixels and same color palette). This brings us
// the best possible to compress the GIF file (using the best
// disposal method to update only the differences between each
// frame).
// * For transparent sprites we offer to the user the option to
// preserve the original palette or not
// (m_preservePaletteOrders). If the palette must be preserve,
// some level of compression will be sacrificed.
//
// 2) For RGB sprites the palette is created on each frame depending
// on the updated rectangle between frames, i.e. each to new frame
// incorporates a minimal rectangular region with changes from the
// previous frame, we can calculate the palette required for this
// rectangle and use it as a local colormap for the frame (if each
// frame uses previous color in the palette there is no need to
// introduce a new palette).
//
// Note: In the following algorithm you will find the "pixel clearing"
// term, this happens when we need to clear an opaque color with the
// gif transparent bg color. This is the worst possible case, because
// on transparent gif files, the only way to get the transparent color
// (bg color) is using the RESTORE_BGCOLOR disposal method (so we lost
// the chance to use DO_NOT_DISPOSE in these cases).
//
class GifEncoder {
public:
typedef int gifframe_t;
@ -904,8 +932,7 @@ public:
, m_hasBackground(m_sprite->isOpaque())
, m_bitsPerPixel(1)
, m_globalColormap(nullptr)
, m_globalColormapPalette(*(m_sprite->palette(0)))
, m_quantizeColormaps(false) {
, m_globalColormapPalette(*m_sprite->palette(0)) {
const auto gifOptions = std::static_pointer_cast<GifOptions>(fop->formatOptions());
@ -916,17 +943,23 @@ public:
m_loop = (gifOptions->loop() ? 0: -1);
if (m_sprite->pixelFormat() == PixelFormat::IMAGE_INDEXED) {
// For indexed and opaque sprite, we can preserve the exact
// palette order without lossing compression rate.
if (m_hasBackground) {
m_preservePaletteOrder = true;
}
// Only for transparent-indexed images we can select if we
// Only for transparent indexed images the user can choose to
// preserve or not the palette order.
else {
m_preservePaletteOrder = gifOptions->preservePaletteOrder();
}
}
else
// For RGB images we don't preserve the palette order (palettes
// will be generated as they are needed to optimize the file
// size).
else {
m_preservePaletteOrder = false;
}
m_lastFrameBounds = m_spriteBounds;
m_lastDisposal = DisposalMethod::NONE;
@ -945,18 +978,19 @@ public:
m_sprite->getPalettes().size() == 1) {
// If some layer has opacity < 255 or a different blend mode, we
// need to create color palettes.
bool quantizeColormaps = false;
for (const Layer* layer : m_sprite->allVisibleLayers()) {
if (layer->isVisible() && layer->isImage()) {
const LayerImage* imageLayer = static_cast<const LayerImage*>(layer);
if (imageLayer->opacity() < 255 ||
imageLayer->blendMode() != BlendMode::NORMAL) {
m_quantizeColormaps = true;
quantizeColormaps = true;
break;
}
}
}
if (!m_quantizeColormaps) {
if (!quantizeColormaps) {
m_globalColormap = createColorMap(&m_globalColormapPalette);
m_bgIndex = m_sprite->transparentColor();
}
@ -965,45 +999,75 @@ public:
}
else {
m_bgIndex = 0;
m_quantizeColormaps = true;
}
// This is the transparent index to use as "local transparent"
// index for each gif frame. In case that we use a global colormap
// (and we don't need to preserve the original palette), we can
// try to find a place for a global transparent index.
m_transparentIndex = (m_hasBackground ? -1: m_bgIndex);
// INDEXED image without Background case: we need to know if 0 color is loaded in the palette:
// Color 0 will be used in the gif file composition when disposal method is DO_NOT_DISPOSE.
// You may think, "Why we do that? In INDEXED we never surpass 256 colors, and we
// simply replacing the entire frame with RESTORE_BGCOLOR is enought".
// Answer: because we want a tiny file size, replacing the entire frame, every frame
// can result in large file sizes. So, we will include the transparent color in
// the final palette, in our case, always the color zero (0).
if (m_globalColormap) {
Palette newPalette(*m_sprite->palette(0));
// The variable m_globalColormap is != nullptr only on indexed images
ASSERT(m_sprite->pixelFormat() == IMAGE_INDEXED);
const Palette* pal = m_sprite->palette(0);
bool maskColorFounded = false;
for (int i=0; i<newPalette.size(); i++) {
if (newPalette.getEntry(i) == 0) {
for (int i=0; i<pal->size(); i++) {
if (doc::rgba_geta(pal->getEntry(i)) == 0) {
maskColorFounded = true;
m_transparentIndex = i;
break;
}
}
if (!maskColorFounded && !m_preservePaletteOrder && !m_hasBackground) {
Palette(0, 255).copyColorsTo(&newPalette);
render::create_palette_from_sprite(m_sprite,
0,
totalFrames()-1,
false,
&newPalette,
nullptr,
m_fop->newBlend(),
false);
#if 0
// If the palette contains room for one extra color for the
// mask, we can use that index.
if (!maskColorFounded && pal->size() < 256) {
maskColorFounded = true;
Palette newPalette(*pal);
newPalette.addEntry(0);
newPalette.copyColorsTo(&m_globalColormapPalette);
m_transparentIndex = m_globalColormapPalette.size() - 1;
ASSERT(newPalette.size() <= 256);
m_transparentIndex = newPalette.size() - 1;
m_globalColormapPalette = newPalette;
m_globalColormap = createColorMap(&m_globalColormapPalette);
}
else
#endif
if (// If all colors are opaque/used in the sprite
!maskColorFounded &&
// We aren't obligated to preserve the original palette
!m_preservePaletteOrder &&
// And the sprite is transparent
!m_hasBackground) {
// We create a new palette with 255 colors + one extra entry
// for the transparent color
Palette newPalette(0, 255);
render::create_palette_from_sprite(
m_sprite,
0,
totalFrames()-1,
false,
&newPalette,
nullptr,
m_fop->newBlend(),
false); // Do not add the transparent color yet
// We will use the last palette entry (e.g. index=255) as the
// transparent index
newPalette.addEntry(0);
ASSERT(newPalette.size() <= 256);
m_transparentIndex = newPalette.size() - 1;
m_globalColormapPalette = newPalette;
m_globalColormap = createColorMap(&m_globalColormapPalette);
}
}
// Create the 3 temporary images (previous/current/next) to
// compare pixels between them.
for (int i=0; i<3; ++i)
m_images[i].reset(Image::create(IMAGE_RGB,
m_spriteBounds.w,
@ -1051,15 +1115,15 @@ public:
if (gifFrame+1 < nframes)
renderFrame(*frame_it, m_nextImage);
gfx::Rect frameBounds(0, 0, m_spriteBounds.w, m_spriteBounds.h);
gfx::Rect frameBounds = m_spriteBounds;
DisposalMethod disposal = DisposalMethod::DO_NOT_DISPOSE;
// Creation of the deltaImage (difference image result respect to
// current VS previous frame image).
// At the same time we must scan the next image,
// to check if some pixel turns to transparent (0),
// if the case, we need to force disposal method of the current image to RESTORE_BG.
// Further, at the same time, we must check if we can go without color zero (0).
// Creation of the deltaImage (difference image result respect
// to current VS previous frame image). At the same time we
// must scan the next image, to check if some pixel turns to
// transparent (0), if the case, we need to force disposal
// method of the current image to RESTORE_BG. Further, at the
// same time, we must check if we can go without color zero (0).
calculateDeltaImageFrameBoundsDisposal(gifFrame, frameBounds, disposal);
@ -1079,17 +1143,17 @@ private:
DisposalMethod& disposal) {
if (gifFrame == 0) {
m_deltaImage.reset(Image::createCopy(m_currentImage));
frameBounds = gfx::Rect(0, 0, m_spriteBounds.w, m_spriteBounds.h);
frameBounds = m_spriteBounds;
// The first frame (frame 0) is good to force to disposal = DO_NOT_DISPOSE,
// but when the next frame (frame 1) has a pixel clearing,
// but when the next frame (frame 1) has a "pixel clearing",
// we must change disposal to RESTORE_BGCOLOR.
// Pixel clearing detection:
// "Pixel clearing" detection:
if (!m_hasBackground) {
const LockImageBits<RgbTraits> bits2(m_currentImage);
const LockImageBits<RgbTraits> bits3(m_nextImage);
typename LockImageBits<RgbTraits>::const_iterator it2, it3, end2, end3;
int i = 0;
for (it2 = bits2.begin(), end2 = bits2.end(),
it3 = bits3.begin(), end3 = bits3.end();
it2 != end2 && it3 != end3; ++it2, ++it3) {
@ -1097,7 +1161,6 @@ private:
disposal = DisposalMethod::RESTORE_BGCOLOR;
break;
}
i++;
}
}
}
@ -1145,18 +1208,14 @@ private:
// we enlarge the frameBounds where the color differences take place
if (*it1 != *it2 || *it3 == 0) {
*deltaIt = *it2;
if (x<x1)
x1 = x;
if (x>x2)
x2 = x;
if (y<y1)
y1 = y;
if (y>y2)
y2 = y;
if (x < x1) x1 = x;
if (x > x2) x2 = x;
if (y < y1) y1 = y;
if (y > y2) y2 = y;
}
// We need to change disposal mode DO_NOT_DISPOSE to RESTORE_BGCOLOR only
// if we found a pixel clearing in the next Image. RESTORE_BGCOLOR is
// if we found a "pixel clearing" in the next Image. RESTORE_BGCOLOR is
// our way to clear pixels.
if (*it2 != 0 && *it3 == 0) {
disposal = DisposalMethod::RESTORE_BGCOLOR;
@ -1188,7 +1247,7 @@ private:
frameBounds = gfx::Rect(0, 0, 1, 1);
m_lastDisposal = disposal;
};
}
doc::frame_t totalFrames() const {
return m_fop->roi().frames();
@ -1288,27 +1347,15 @@ private:
const gfx::Rect& frameBounds,
const DisposalMethod disposal,
const bool fixDuration) {
std::unique_ptr<RgbMap> rgbmapRef;
Palette framePalette(*m_sprite->palette(0));
RgbMap* rgbmap(m_sprite->rgbMap(0));
if (m_globalColormap) {
m_globalColormapPalette.copyColorsTo(&framePalette);
rgbmapRef.reset(new RgbMap);
rgbmapRef.get()->regenerate(&framePalette, m_transparentIndex);
}
Palette framePalette;
if (m_globalColormap)
framePalette = m_globalColormapPalette;
else
m_sprite->palette(frame)->copyColorsTo(&framePalette);
framePalette = calculatePalette(frameBounds, disposal);
RgbMap rgbmap;
rgbmap.regenerate(&framePalette, m_transparentIndex);
if (m_quantizeColormaps) {
calculatePalette(frameBounds, disposal).copyColorsTo(&framePalette);
rgbmapRef.reset(new RgbMap);
rgbmapRef.get()->regenerate(&framePalette, m_transparentIndex);
}
rgbmap = rgbmapRef.get();
ImageRef frameImage(Image::create(IMAGE_INDEXED,
frameBounds.w,
frameBounds.h,
@ -1342,10 +1389,9 @@ private:
255,
m_transparentIndex);
if (i < 0)
i = rgbmap->mapColor(rgba_getr(color),
rgba_getg(color),
rgba_getb(color),
255);
i = rgbmap.mapColor(rgba_getr(color),
rgba_getg(color),
rgba_getb(color), 255);
}
else {
if (m_transparentIndex >= 0)
@ -1443,13 +1489,15 @@ private:
GifFreeMapObject(colormap);
}
Palette calculatePalette(const gfx::Rect& frameBounds, DisposalMethod disposal) {
Palette calculatePalette(const gfx::Rect& frameBounds,
const DisposalMethod disposal) {
// First, we must check the palette color count in m_deltaImage (our best shot
// to find the smaller palette color count)
Palette pal(createOptimizedPalette(m_deltaImage.get(), m_deltaImage->bounds(), 257));
Palette pal(createOptimizedPalette(m_deltaImage.get(), m_deltaImage->bounds(), 256));
if (pal.size() == 256) {
// Here, the palette has 256 colors, there is no place to include the 0 color ( remember,
// createOptimizedPalette do not create entry for it).
// Here the palette has 256 colors, there is no place to include
// the 0 color (createOptimizedPalette() doesn't create an entry
// for it).
//
// We have two paths:
// 1- Giving a try to palette generation on m_currentImage in frameBouns limits.
@ -1459,14 +1507,17 @@ private:
// 1- Giving a try to palette generation on m_currentImage in frameBouns limits.
// if disposal == RESTORE_BGCOLOR m_deltaImage already is a cropped copy of m_currentImage.
Palette auxPalette(pal);
Palette auxPalette;
if (disposal == DisposalMethod::DO_NOT_DISPOSE)
createOptimizedPalette(m_currentImage, frameBounds, 257).copyColorsTo(&auxPalette);
auxPalette = createOptimizedPalette(m_currentImage, frameBounds, 257);
else
auxPalette = pal;
if (auxPalette.size() <= 256) {
// We are fine with color count in m_currentImage contained in frameBouns (we got 256 or less colors):
// We are fine with color count in m_currentImage contained in
// frameBounds (we got 256 or less colors):
m_transparentIndex = -1;
auxPalette.copyColorsTo(&pal);
pal = auxPalette;
if (disposal == DisposalMethod::DO_NOT_DISPOSE)
m_deltaImage.reset(crop_image(m_currentImage, frameBounds, 0));
}
@ -1494,15 +1545,16 @@ private:
// |_______________________________|
//
int thicknessTop = m_deltaImage->bounds().h / 4;
int thicknessLeft = m_deltaImage->bounds().w / 4;
const gfx::Size deltaSize = m_deltaImage->size();
int thicknessTop = deltaSize.h / 4;
int thicknessLeft = deltaSize.w / 4;
int lastThicknessTop = thicknessTop;
int lastThicknessLeft = thicknessLeft;
while (true) {
render::PaletteOptimizer optimizer;
gfx::Rect auxRect(0, 0, m_deltaImage->bounds().w, thicknessTop);
optimizer.feedWithImage(Image::createCopy(crop_image(m_deltaImage.get(), auxRect, m_transparentIndex)), false);
gfx::Rect auxRect(0, 0, deltaSize.w, thicknessTop);
optimizer.feedWithImage(m_deltaImage.get(), auxRect, false);
// ----------------
// |________________|
// | | | |
@ -1510,8 +1562,8 @@ private:
// | |________| |
// |________________|
auxRect = gfx::Rect(0, m_deltaImage->bounds().h - thicknessTop, m_deltaImage->bounds().w, thicknessTop);
optimizer.feedWithImage(Image::createCopy(crop_image(m_deltaImage.get(), auxRect, m_transparentIndex)), false);
auxRect = gfx::Rect(0, deltaSize.h - thicknessTop, deltaSize.w, thicknessTop);
optimizer.feedWithImage(m_deltaImage.get(), auxRect, false);
// ----------------
// | ________ |
// | | | |
@ -1519,8 +1571,8 @@ private:
// |___|________|___|
// |________________|
auxRect = gfx::Rect(0, thicknessTop, thicknessLeft, m_deltaImage->bounds().h - 2 * thicknessTop);
optimizer.feedWithImage(Image::createCopy(crop_image(m_deltaImage.get(), auxRect, m_transparentIndex)), false);
auxRect = gfx::Rect(0, thicknessTop, thicknessLeft, deltaSize.h - 2 * thicknessTop);
optimizer.feedWithImage(m_deltaImage.get(), auxRect, false);
// ----------------
// |____________ |
// | | | |
@ -1528,8 +1580,8 @@ private:
// |___|________| |
// |________________|
auxRect = gfx::Rect(m_deltaImage->bounds().w - thicknessLeft, thicknessTop, thicknessLeft, m_deltaImage->bounds().h - 2 * thicknessTop);
optimizer.feedWithImage(Image::createCopy(crop_image(m_deltaImage.get(), auxRect, m_transparentIndex)), false);
auxRect = gfx::Rect(deltaSize.w - thicknessLeft, thicknessTop, thicknessLeft, deltaSize.h - 2 * thicknessTop);
optimizer.feedWithImage(m_deltaImage.get(), auxRect, false);
// ----------------
// | _____________|
// | | | |
@ -1539,14 +1591,14 @@ private:
if (optimizer.isHighPrecision()) {
if (optimizer.highPrecisionSize() >= 220) { // 220 colors is an arbitrary number
lastThicknessTop = thicknessTop;
lastThicknessLeft = thicknessLeft;
lastThicknessTop = thicknessTop;
lastThicknessLeft = thicknessLeft;
// Put the high precision colors to the palette:
optimizer.calculate(&pal, 0);
break;
}
else if (m_deltaImage->bounds().h - thicknessTop * 2 <= m_deltaImage->bounds().h / 4 ||
m_deltaImage->bounds().w - thicknessLeft * 2 <= m_deltaImage->bounds().w / 4) {
else if (deltaSize.h - thicknessTop * 2 <= deltaSize.h / 4 ||
deltaSize.w - thicknessLeft * 2 <= deltaSize.w / 4) {
// Put the high precision colors to the palette:
optimizer.calculate(&pal, 0);
break;
@ -1555,8 +1607,8 @@ private:
thicknessLeft += thicknessLeft / 2;
}
else {
if (thicknessTop <= m_deltaImage->bounds().h / 16 ||
thicknessLeft <= m_deltaImage->bounds().w / 16) {
if (thicknessTop <= deltaSize.h / 16 ||
thicknessLeft <= deltaSize.w / 16) {
// TODO: we need to catch this LAST posibility.
// Put the high precision colors to the palette:
optimizer.calculate(&pal, 0);
@ -1571,19 +1623,20 @@ private:
}
gfx::Rect centerRect(lastThicknessLeft,
lastThicknessTop,
m_deltaImage->bounds().w - 1 - lastThicknessLeft,
m_deltaImage->bounds().h - 1 - lastThicknessTop);
deltaSize.w - 1 - lastThicknessLeft,
deltaSize.h - 1 - lastThicknessTop);
// Find the center colors (aproximation colors)
Palette centerPalette(createOptimizedPalette(m_deltaImage.get(), centerRect, 255 - pal.size()));
// Adding the center colors to pal
Palette centerPalette(
createOptimizedPalette(m_deltaImage.get(),
centerRect, 255 - pal.size()));
// Adding the center colors to pal + transparent color
for (int i=0; i < centerPalette.size(); i++)
pal.addEntry(centerPalette.getEntry(i));
// Add the transparent color:
pal.addEntry(0);
m_transparentIndex = pal.size() - 1;
}
}
// We are fine, we got 255 or less:
// We are fine, we got 255 or less, there is room for the transparent color
else if (pal.size() <= 255) {
pal.addEntry(0);
m_transparentIndex = pal.size() - 1;
@ -1591,10 +1644,12 @@ private:
return pal;
}
Palette createOptimizedPalette(Image* image, gfx::Rect bounds, int ncolors = 256) {
static Palette createOptimizedPalette(const Image* image,
const gfx::Rect& bounds,
const int ncolors) {
render::PaletteOptimizer optimizer;
// Feed the palette optimizer with pixels inside frameBounds
// Feed the palette optimizer with pixels inside the given bounds
for (const auto& color : LockImageBits<RgbTraits>(image, bounds)) {
if (rgba_geta(color) >= 128) // Note: the mask color won't be part of the final palette
optimizer.feedWithRgbaColor(
@ -1653,9 +1708,10 @@ private:
int m_bgIndex;
int m_transparentIndex;
int m_bitsPerPixel;
// Global palette to use on all frames, or nullptr in case that we
// have to quantize the palette on each frame.
ColorMapObject* m_globalColormap;
Palette m_globalColormapPalette;
bool m_quantizeColormaps;
bool m_interlaced;
int m_loop;
bool m_preservePaletteOrder;

2
src/doc/LICENSE.txt
View File

@ -1,4 +1,4 @@
Copyright (c) 2018-2019 Igara Studio S.A.
Copyright (c) 2018-2020 Igara Studio S.A.
Copyright (c) 2001-2018 David Capello
Permission is hereby granted, free of charge, to any person obtaining

17
src/doc/palette.cpp
View File

@ -22,6 +22,11 @@ namespace doc {
using namespace gfx;
Palette::Palette()
: Palette(0, 256)
{
}
Palette::Palette(frame_t frame, int ncolors)
: Object(ObjectType::Palette)
{
@ -58,6 +63,18 @@ Palette::~Palette()
{
}
Palette& Palette::operator=(const Palette& that)
{
m_frame = that.m_frame;
m_colors = that.m_colors;
m_names = that.m_names;
m_filename = that.m_filename;
m_comment = that.m_comment;
++m_modifications;
return *this;
}
Palette* Palette::createGrayscale()
{
Palette* graypal = new Palette(frame_t(0), 256);

6
src/doc/palette.h
View File

@ -1,5 +1,6 @@
// Aseprite Document Library
// Copyright (c) 2001-2018 David Capello
// Copyright (C) 2020 Igara Studio S.A.
// Copyright (C) 2001-2018 David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.
@ -22,11 +23,14 @@ namespace doc {
class Palette : public Object {
public:
Palette();
Palette(frame_t frame, int ncolors);
Palette(const Palette& palette);
Palette(const Palette& palette, const Remap& remap);
~Palette();
Palette& operator=(const Palette& that);
static Palette* createGrayscale();
int size() const { return (int)m_colors.size(); }

18
src/render/quantization.cpp
View File

@ -348,7 +348,15 @@ Image* convert_pixel_format(
// Creation of optimized palette for RGB images
// by David Capello
void PaletteOptimizer::feedWithImage(Image* image, bool withAlpha)
void PaletteOptimizer::feedWithImage(const Image* image,
const bool withAlpha)
{
feedWithImage(image, image->bounds(), withAlpha);
}
void PaletteOptimizer::feedWithImage(const Image* image,
const gfx::Rect& bounds,
const bool withAlpha)
{
uint32_t color;
@ -360,8 +368,8 @@ void PaletteOptimizer::feedWithImage(Image* image, bool withAlpha)
case IMAGE_RGB:
{
const LockImageBits<RgbTraits> bits(image);
LockImageBits<RgbTraits>::const_iterator it = bits.begin(), end = bits.end();
const LockImageBits<RgbTraits> bits(image, bounds);
auto it = bits.begin(), end = bits.end();
for (; it != end; ++it) {
color = *it;
@ -377,8 +385,8 @@ void PaletteOptimizer::feedWithImage(Image* image, bool withAlpha)
case IMAGE_GRAYSCALE:
{
const LockImageBits<RgbTraits> bits(image);
LockImageBits<RgbTraits>::const_iterator it = bits.begin(), end = bits.end();
const LockImageBits<GrayscaleTraits> bits(image, bounds);
auto it = bits.begin(), end = bits.end();
for (; it != end; ++it) {
color = *it;

6
src/render/quantization.h
View File

@ -28,7 +28,11 @@ namespace render {
class PaletteOptimizer {
public:
void feedWithImage(doc::Image* image, bool withAlpha);
void feedWithImage(const doc::Image* image,
const bool withAlpha);
void feedWithImage(const doc::Image* image,
const gfx::Rect& bounds,
const bool withAlpha);
void feedWithRgbaColor(doc::color_t color);
void calculate(doc::Palette* palette, int maskIndex);
bool isHighPrecision() { return m_histogram.isHighPrecision(); }