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Optimize frame comparison #72

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merged 5 commits into from
Aug 13, 2024
Merged

Optimize frame comparison #72

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3c2ecf1
split out different area calculation
tlsa Jun 24, 2024
2baf0e1
optimize getDiffArea for global palette case
tlsa Jun 24, 2024
0d08c2e
optimize same frame detection in global palette case
tlsa Jun 24, 2024
f931c91
add tests for user defined transparency frame diff and merge
dloebl Aug 13, 2024
94a67d1
fast frame diff path: add checks for user defined transparency
dloebl Aug 13, 2024
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144 changes: 123 additions & 21 deletions src/cgif.c
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Original file line number Diff line number Diff line change
Expand Up @@ -155,9 +155,8 @@ static int cmpPixel(const CGIF* pGIF, const CGIF_FrameConfig* pCur, const CGIF_F
return memcmp(pBefCT + iBef * 3, pCurCT + iCur * 3, 3);
}

/* optimize GIF file size by only redrawing the rectangular area that differs from previous frame */
static uint8_t* doWidthHeightOptim(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_FrameConfig* pBef, DimResult* pResult) {
uint8_t* pNewImageData;
// compare given frames; returns 0 if frames are equal and 1 if they differ. If they differ, pResult returns area of difference
static int getDiffArea(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_FrameConfig* pBef, DimResult *pResult) {
const uint8_t* pCurImageData;
const uint8_t* pBefImageData;
uint16_t i, x;
Expand All @@ -181,13 +180,8 @@ static uint8_t* doWidthHeightOptim(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_Fram
++i;
}
FoundTop:
if(i == height) { // need dummy pixel (frame is identical with one before)
// TBD we might make it possible to merge identical frames in the future
newWidth = 1;
newHeight = 1;
newLeft = 0;
newTop = 0;
goto Done;
if(i == height) {
return 0;
}
newTop = i;

Expand All @@ -212,7 +206,7 @@ static uint8_t* doWidthHeightOptim(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_Fram
while(cmpPixel(pGIF, pCur, pBef, pCurImageData[MULU16(i, width) + x], pBefImageData[MULU16(i, width) + x]) == 0) {
++i;
if(i > (newTop + newHeight - 1)) {
++x; //(x==width cannot happen as goto Done is triggered in the only possible case before)
++x; //(x==width cannot happen as return 0 is trigged in the only possible case before)
i = newTop;
}
}
Expand All @@ -224,25 +218,126 @@ static uint8_t* doWidthHeightOptim(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_Fram
while(cmpPixel(pGIF, pCur, pBef, pCurImageData[MULU16(i, width) + x], pBefImageData[MULU16(i, width) + x]) == 0) {
++i;
if(i > (newTop + newHeight - 1)) {
--x; //(x<newLeft cannot happen as goto Done is triggered in the only possible case before)
--x; //(x<newLeft cannot happen as return 0 is trigged in the only possible case before)
i = newTop;
}
}
newWidth = (x + 1) - newLeft;

Done:
pResult->width = newWidth;
pResult->height = newHeight;
pResult->top = newTop;
pResult->left = newLeft;
return 1;
}

// compare given global palette frames; returns 0 if frames are equal and 1 if they differ. If they differ, pResult returns area of difference
static int getDiffAreaGlobalPalette(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_FrameConfig* pBef, DimResult *pResult) {
const uint8_t* pCurImageData;
const uint8_t* pBefImageData;
uint16_t i, x;
uint16_t newHeight, newWidth, newLeft, newTop;
const uint16_t width = pGIF->config.width;
const uint16_t height = pGIF->config.height;
size_t offset;

// create new image data
pNewImageData = malloc(MULU16(newWidth, newHeight)); // TBD check return value of malloc
for (i = 0; i < newHeight; ++i) {
memcpy(pNewImageData + MULU16(i, newWidth), pCurImageData + MULU16((i + newTop), width) + newLeft, newWidth);
pCurImageData = pCur->pImageData;
pBefImageData = pBef->pImageData;
// find top
i = 0;
offset = 0;
while(i < height) {
if (memcmp(pCurImageData + offset, pBefImageData + offset, width)) {
break;
}
++i;
offset += width;
}

if(i == height) {
return 0;
}
newTop = i;

// find actual height
i = height - 1;
offset = i * width;
while(i > newTop) {
if (memcmp(pCurImageData + offset, pBefImageData + offset, width)) {
break;
}
--i;
offset -= width;
}
newHeight = (i + 1) - newTop;

// find left
i = newTop;
x = 0;
offset = i * width;
while(pCurImageData[offset + x] == pBefImageData[offset + x]) {
++i;
offset += width;
if(i > (newTop + newHeight - 1)) {
++x; //(x==width cannot happen as return 0 is triggered in the only possible case before)
i = newTop;
offset = i * width;
}
}
newLeft = x;

// find actual width
i = newTop;
x = width - 1;
offset = i * width;
while(pCurImageData[offset + x] == pBefImageData[offset + x]) {
++i;
offset += width;
if(i > (newTop + newHeight - 1)) {
--x; //(x<newLeft cannot happen as return 0 is triggered in the only possible case before)
i = newTop;
offset = i * width;
}
}
newWidth = (x + 1) - newLeft;

// set new width, height, top, left in DimResult struct
pResult->width = newWidth;
pResult->height = newHeight;
pResult->top = newTop;
pResult->left = newLeft;
return 1;
}

/* optimize GIF file size by only redrawing the rectangular area that differs from previous frame */
static uint8_t* doWidthHeightOptim(CGIF* pGIF, CGIF_FrameConfig* pCur, CGIF_FrameConfig* pBef, DimResult* pResult) {
uint16_t i;
uint8_t* pNewImageData;
const uint16_t width = pGIF->config.width;
const uint8_t* pCurImageData = pCur->pImageData;
int diffFrame;

if ((pBef->attrFlags & CGIF_FRAME_ATTR_USE_LOCAL_TABLE) == 0 && (pCur->attrFlags & CGIF_FRAME_ATTR_USE_LOCAL_TABLE) == 0
&& (pBef->attrFlags & CGIF_FRAME_ATTR_HAS_SET_TRANS) == 0 && (pCur->attrFlags & CGIF_FRAME_ATTR_HAS_SET_TRANS) == 0) {
// Both frames use global palette; use fast comparison.
diffFrame = getDiffAreaGlobalPalette(pGIF, pCur, pBef, pResult);
} else {
diffFrame = getDiffArea(pGIF, pCur, pBef, pResult);
}

if (diffFrame == 0) { // need dummy pixel (frame is identical with one before)
// TBD we might make it possible to merge identical frames in the future
pResult->width = 1;
pResult->height = 1;
pResult->left = 0;
pResult->top = 0;
}

// create new image data
pNewImageData = malloc(MULU16(pResult->width, pResult->height)); // TBD check return value of malloc
for (i = 0; i < pResult->height; ++i) {
memcpy(pNewImageData + MULU16(i, pResult->width), pCurImageData + MULU16((i + pResult->top), width) + pResult->left, pResult->width);
}

return pNewImageData;
}

Expand Down Expand Up @@ -401,10 +496,17 @@ int cgif_addframe(CGIF* pGIF, CGIF_FrameConfig* pConfig) {
const uint32_t frameDelay = pConfig->delay + pGIF->aFrames[pGIF->iHEAD]->config.delay;
if(frameDelay <= 0xFFFF && !(pGIF->config.genFlags & CGIF_GEN_KEEP_IDENT_FRAMES)) {
int sameFrame = 1;
for(i = 0; i < pGIF->config.width * pGIF->config.height; i++) {
if(cmpPixel(pGIF, pConfig, &pGIF->aFrames[pGIF->iHEAD]->config, pConfig->pImageData[i], pGIF->aFrames[pGIF->iHEAD]->config.pImageData[i])) {
if ((pConfig->attrFlags & CGIF_FRAME_ATTR_USE_LOCAL_TABLE) == 0 && (pGIF->aFrames[pGIF->iHEAD]->config.attrFlags & CGIF_FRAME_ATTR_USE_LOCAL_TABLE) == 0
&& (pConfig->attrFlags & CGIF_FRAME_ATTR_HAS_SET_TRANS) == 0 && (pGIF->aFrames[pGIF->iHEAD]->config.attrFlags & CGIF_FRAME_ATTR_HAS_SET_TRANS) == 0) {
if (memcmp(pConfig->pImageData, pGIF->aFrames[pGIF->iHEAD]->config.pImageData, pGIF->config.width * pGIF->config.height)) {
sameFrame = 0;
break;
}
} else {
for(i = 0; i < pGIF->config.width * pGIF->config.height; i++) {
if(cmpPixel(pGIF, pConfig, &pGIF->aFrames[pGIF->iHEAD]->config, pConfig->pImageData[i], pGIF->aFrames[pGIF->iHEAD]->config.pImageData[i])) {
sameFrame = 0;
break;
}
}
}

Expand Down
2 changes: 2 additions & 0 deletions tests/meson.build
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,8 @@ tests = [
{ 'name' : 'stripe_pattern_interlaced', 'seed_should_fail' : false},
{ 'name' : 'switchpattern', 'seed_should_fail' : false},
{ 'name' : 'trans_inc_initdict', 'seed_should_fail' : false},
{ 'name' : 'user_trans_diff_area', 'seed_should_fail' : false},
{ 'name' : 'user_trans_merge', 'seed_should_fail' : false},
{ 'name' : 'user_trans', 'seed_should_fail' : false},
{ 'name' : 'write_fn', 'seed_should_fail' : false},
]
Expand Down
2 changes: 2 additions & 0 deletions tests/tests.sha256
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Original file line number Diff line number Diff line change
Expand Up @@ -34,5 +34,7 @@ ff1da19b0448af07d8561f0ee62b184f99ac7dcb75f1a2215474190ec6648901 noise6.gif
161a132972bfbc060ea0359d8c40513d2e22e65b27a7c11553f883fe3856fe30 stripe_pattern_interlaced.gif
b8a7e72024a1263229e85f27168800400489cf993f7b90f45f00d39323763261 switchpattern.gif
1eb29910b6633bc1c6be49fc85ba7f5c24f415083d81f35c366ea50d55bcdf8d trans_inc_initdict.gif
0e02f2440b2db58268f6ef7906e41b088177e9fcdb2cb37e9540f4bfc9a7fa17 user_trans_diff_area.gif
55b64d9c9a359f9daeecdf55c83e485aca3f90d2a6dd29f86d5b14a0e1396770 user_trans.gif
86a08337540a8332dea3cb092394c3aac04fbbe98d9d884eb169a6c85d20f9a6 user_trans_merge.gif
5d301094a0b54287cabcc71c6972f7be417a5bea87cde01d85089a8893fd17fd write_fn.gif
62 changes: 62 additions & 0 deletions tests/user_trans_diff_area.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,62 @@
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "cgif.h"

#define WIDTH 2
#define HEIGHT 2

int main(void) {
CGIF* pGIF;
CGIF_Config gConfig;
CGIF_FrameConfig fConfig;
uint8_t* pImageData;
uint8_t aPalette[] = {
0x00, 0xFF, 0x00, // green
0xFF, 0xFF, 0xFF, // white
};
cgif_result r;

memset(&gConfig, 0, sizeof(CGIF_Config));
memset(&fConfig, 0, sizeof(CGIF_FrameConfig));
gConfig.attrFlags = CGIF_ATTR_IS_ANIMATED;
gConfig.genFlags = CGIF_GEN_KEEP_IDENT_FRAMES;
gConfig.width = WIDTH;
gConfig.height = HEIGHT;
gConfig.pGlobalPalette = aPalette;
gConfig.numGlobalPaletteEntries = 2;
gConfig.path = "user_trans_diff_area.gif";
//
// create new GIF
pGIF = cgif_newgif(&gConfig);
if(pGIF == NULL) {
fputs("failed to create new GIF via cgif_newgif()\n", stderr);
return 1;
}
//
// add frames to GIF
pImageData = malloc(WIDTH * HEIGHT);
memset(pImageData, 0, WIDTH * HEIGHT);
fConfig.pImageData = pImageData;
fConfig.delay = 500;
cgif_addframe(pGIF, &fConfig);
fConfig.attrFlags = CGIF_FRAME_ATTR_HAS_SET_TRANS;
fConfig.genFlags = CGIF_FRAME_GEN_USE_DIFF_WINDOW;
fConfig.transIndex = 1;
// set everything to transparent (frame from before shines through)
memset(pImageData, 1, WIDTH * HEIGHT);
r = cgif_addframe(pGIF, &fConfig);
free(pImageData);
//
// write GIF to file
r = cgif_close(pGIF);

// check for errors
if(r != CGIF_OK) {
fprintf(stderr, "failed to create GIF. error code: %d\n", r);
return 2;
}
return 0;
}
61 changes: 61 additions & 0 deletions tests/user_trans_merge.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,61 @@
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "cgif.h"

#define WIDTH 2
#define HEIGHT 2

int main(void) {
CGIF* pGIF;
CGIF_Config gConfig;
CGIF_FrameConfig fConfig;
uint8_t* pImageData;
uint8_t aPalette[] = {
0x00, 0xFF, 0x00, // green
0xFF, 0xFF, 0xFF, // white
};
cgif_result r;

memset(&gConfig, 0, sizeof(CGIF_Config));
memset(&fConfig, 0, sizeof(CGIF_FrameConfig));
gConfig.attrFlags = CGIF_ATTR_IS_ANIMATED;
gConfig.width = WIDTH;
gConfig.height = HEIGHT;
gConfig.pGlobalPalette = aPalette;
gConfig.numGlobalPaletteEntries = 2;
gConfig.path = "user_trans_merge.gif";
//
// create new GIF
pGIF = cgif_newgif(&gConfig);
if(pGIF == NULL) {
fputs("failed to create new GIF via cgif_newgif()\n", stderr);
return 1;
}
//
// add frames to GIF
pImageData = malloc(WIDTH * HEIGHT);
memset(pImageData, 0, WIDTH * HEIGHT);
fConfig.pImageData = pImageData;
fConfig.delay = 500;
cgif_addframe(pGIF, &fConfig);
fConfig.attrFlags = CGIF_FRAME_ATTR_HAS_SET_TRANS;
fConfig.genFlags = CGIF_FRAME_GEN_USE_DIFF_WINDOW;
fConfig.transIndex = 1;
// set everything to transparent (frame from before shines through)
memset(pImageData, 1, WIDTH * HEIGHT);
r = cgif_addframe(pGIF, &fConfig);
free(pImageData);
//
// write GIF to file
r = cgif_close(pGIF);

// check for errors
if(r != CGIF_OK) {
fprintf(stderr, "failed to create GIF. error code: %d\n", r);
return 2;
}
return 0;
}
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