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gifdecoder bugfixes, up to 30% speedup, and minor improvements #279

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Merged
softhack007 merged 8 commits into from
Nov 7, 2025
Merged

gifdecoder bugfixes, up to 30% speedup, and minor improvements #279

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10b3ac0
gifdecoder speedup and bugfixes
softhack007 Nov 6, 2025
698da84
prevent division by zero when image width or height is 0
softhack007 Nov 6, 2025
25391fe
try to catch / handle Gif decoder OOM gracefully
softhack007 Nov 6, 2025
9564791
prevent string underflow
softhack007 Nov 6, 2025
f955df0
camelCase, future support, minor cleanup
softhack007 Nov 7, 2025
9115cd1
tiny cleanup, ready to merge
softhack007 Nov 7, 2025
c58c6ef
minor robustness improvement
softhack007 Nov 7, 2025
c1979f8
no fun in Germany ;-)
softhack007 Nov 7, 2025
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4 changes: 3 additions & 1 deletion wled00/FX.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4693,9 +4693,11 @@ static const char _data_FX_MODE_WASHING_MACHINE[] PROGMEM = "Washing Machine@!,!
Draws a .gif image from filesystem on the matrix/strip
*/
uint16_t mode_image(void) {
if (!strip.isMatrix) return mode_oops(); // not a 2D set-up
#ifndef WLED_ENABLE_GIF
return mode_oops();
#else
if (max(SEGMENT.virtualWidth(),SEGMENT.virtualHeight()) < 4) return mode_oops(); // too small
renderImageToSegment(SEGMENT);
return FRAMETIME;
#endif
Expand All @@ -4704,7 +4706,7 @@ uint16_t mode_image(void) {
// Serial.println(status);
// }
}
static const char _data_FX_MODE_IMAGE[] PROGMEM = "Image@!,;;;12;sx=128";
static const char _data_FX_MODE_IMAGE[] PROGMEM = "Image@!,Blur,;;;12;sx=128,ix=0";

/*
Blends random colors across palette
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110 changes: 88 additions & 22 deletions wled00/image_loader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,11 +9,15 @@
* Functions to render images from filesystem to segments, used by the "Image" effect
*/

File file;
char lastFilename[34] = "/";
GifDecoder<320,320,12,true> decoder;
bool gifDecodeFailed = false;
unsigned long lastFrameDisplayTime = 0, currentFrameDelay = 0;
static File file;
static char lastFilename[34] = "/";
#if !defined(BOARD_HAS_PSRAM)
static GifDecoder<256,256,11,true> decoder; // WLEDMM use less RAM on boards without PSRAM - avoids crashes due to out-of-memory
#else
static GifDecoder<320,320,12,true> decoder;
#endif
static bool gifDecodeFailed = false;
static unsigned long lastFrameDisplayTime = 0, currentFrameDelay = 0;

bool fileSeekCallback(unsigned long position) {
return file.seek(position);
Expand All @@ -35,29 +39,49 @@ int fileSizeCallback(void) {
return file.size();
}

bool openGif(const char *filename) {
bool openGif(const char *filename) { // side-effect: updates "file"
file = WLED_FS.open(filename, "r");
DEBUG_PRINTF("opening GIF file %s\n", filename);

if (!file) return false;
return true;
}

Segment* activeSeg;
uint16_t gifWidth, gifHeight;
static Segment* activeSeg;
static uint16_t gifWidth, gifHeight; // these two must stay uint16_t, because they are passed by reference
static unsigned segCols = 1;
static unsigned segRows = 1;
//static unsigned segLen = 1; // for future 1D support
static int expandX = 1;
static int expandY = 1;
static int lastX = -1, lastY = -1;

void screenClearCallback(void) {
activeSeg->fill(0);
}

void updateScreenCallback(void) {}
void updateScreenCallback(void) {
// this callback runs when the decoder has finished painting all pixels
// perfect time for adding blur
if (activeSeg->intensity > 1) {
uint8_t blurAmount = activeSeg->intensity >> 2;
if ((blurAmount < 24) && (activeSeg->is2D())) activeSeg->blurRows(activeSeg->intensity >> 1); // some blur - fast
else activeSeg->blur(blurAmount); // more blur - slower
}
lastX = lastY = -1; // invalidate last position
}
void draw2DPixelCallback(int16_t x, int16_t y, uint8_t red, uint8_t green, uint8_t blue) {
// simple nearest-neighbor downscaling
int outY = y * segRows / gifHeight;
int outX = x * segCols / gifWidth;
if ((unsigned(outX) >= segCols) || (unsigned(outY) >= segRows)) return; // out of range
if ((lastX == outX) && (lastY == outY)) return; // downscaling optimization: skip re-painting same pixel
lastX = outX; lastY = outY;

void drawPixelCallback(int16_t x, int16_t y, uint8_t red, uint8_t green, uint8_t blue) {
// simple nearest-neighbor scaling
int16_t outY = y * activeSeg->height() / gifHeight;
int16_t outX = x * activeSeg->width() / gifWidth;
// set multiple pixels if upscaling
for (int16_t i = 0; i < (activeSeg->width()+(gifWidth-1)) / gifWidth; i++) {
for (int16_t j = 0; j < (activeSeg->height()+(gifHeight-1)) / gifHeight; j++) {
// softhack007: changed loop x/y order -> minor speedup from better cache locality
for (int j = 0; j < expandY; j++) {
for (int i = 0; i < expandX; i++) {
activeSeg->setPixelColorXY(outX + i, outY + j, gamma8(red), gamma8(green), gamma8(blue));
}
}
Expand All @@ -81,28 +105,57 @@ byte renderImageToSegment(Segment &seg) {
// TODO: if (seg.mode != seg.currentMode()) return IMAGE_ERROR_WAITING;
if (activeSeg && activeSeg != &seg) return IMAGE_ERROR_SEG_LIMIT; // only one segment at a time
activeSeg = &seg;
segCols = activeSeg->virtualWidth();
segRows = activeSeg->virtualHeight();
// segLen = activeSeg->virtualLength(); // for future 1D and expand1D support

if (strncmp(lastFilename +1, seg.name, 32) != 0) { // segment name changed, load new image
strncpy(lastFilename +1, seg.name, 32);
gifDecodeFailed = false;
if (strcmp(lastFilename + strlen(lastFilename) - 4, ".gif") != 0) {
size_t fnameLen = strlen(lastFilename);
if ((fnameLen < 4) || strcmp(lastFilename + fnameLen - 4, ".gif") != 0) { // empty segment name, name too short, or name not ending in .gif

@softhack007 softhack007 Nov 7, 2025 •
edited
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open ends (will not fix in this PR):

  • compare should be case-insensitive - ".GIF", ".Gif", ".gIf" should be accepted.
    esp32 does not have "stricmp", so we might need a custom solution, maybe with a utility function that internally uses tolower(c) before comparing.
  • strip leading / trailing blanks from the filename.

gifDecodeFailed = true;
USER_PRINTF("GIF decoder unsupported file: %s\n", lastFilename);
return IMAGE_ERROR_UNSUPPORTED_FORMAT;
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}
if (file) file.close();
openGif(lastFilename);
if (!file) { gifDecodeFailed = true; return IMAGE_ERROR_FILE_MISSING; }

if (!openGif(lastFilename)) {
gifDecodeFailed = true;
USER_PRINTF("GIF file not found: %s\n", lastFilename);
return IMAGE_ERROR_FILE_MISSING;
}
decoder.setScreenClearCallback(screenClearCallback);
decoder.setUpdateScreenCallback(updateScreenCallback);
decoder.setDrawPixelCallback(drawPixelCallback);
decoder.setDrawPixelCallback(draw2DPixelCallback);
decoder.setFileSeekCallback(fileSeekCallback);
decoder.setFilePositionCallback(filePositionCallback);
decoder.setFileReadCallback(fileReadCallback);
decoder.setFileReadBlockCallback(fileReadBlockCallback);
decoder.setFileSizeCallback(fileSizeCallback);
decoder.alloc();
#if __cpp_exceptions // use exception handler if we can (some targets don't support exceptions)
try {
#endif
decoder.alloc(); // WLEDMM this function may throw out-of memory and cause a crash
#if __cpp_exceptions
} catch (...) { // if we arrive here, the decoder has thrown an OOM exception
gifDecodeFailed = true;
errorFlag = ERR_NORAM_PX;
USER_PRINTLN("\nGIF decoder out of memory. I'm going to shoot myself now.\n");
return IMAGE_ERROR_DECODER_ALLOC;
}
#endif
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coderabbitai[bot] marked this conversation as resolved.

DEBUG_PRINTLN(F("Starting decoding"));
if(decoder.startDecoding() < 0) { gifDecodeFailed = true; return IMAGE_ERROR_GIF_DECODE; }
int derr = 0;
if((derr = decoder.startDecoding()) < 0) {
gifDecodeFailed = true;
USER_PRINTF("GIF Decoding error %d\n", derr);
if ((derr == ERROR_GIF_TOO_WIDE) || (derr == ERROR_GIF_UNSUPPORTED_FEATURE) || (derr == ERROR_GIF_INVALID_PARAMETER))
errorFlag = ERR_NORAM_PX;
return IMAGE_ERROR_GIF_DECODE;
}
if ((errorFlag == ERR_NORAM_PX) || (errorFlag == ERR_NORAM)) errorFlag = ERR_NONE; // success -> reset previous memory error codes
DEBUG_PRINTLN(F("Decoding started"));
}

Expand All @@ -118,9 +171,22 @@ byte renderImageToSegment(Segment &seg) {
if (millis() - lastFrameDisplayTime < wait) return IMAGE_ERROR_WAITING;

decoder.getSize(&gifWidth, &gifHeight);
// bad gif size: prevent division by zero
if (gifWidth == 0 || gifHeight == 0) {
gifDecodeFailed = true;
USER_PRINTF("Invalid GIF dimensions: %dx%d\n", gifWidth, gifHeight);
return IMAGE_ERROR_GIF_DECODE;
}
// softhack007: pre-calculate upscaling for speedup
expandX = (segCols+(gifWidth-1)) / gifWidth;
expandY = (segRows+(gifHeight-1)) / gifHeight;

int result = decoder.decodeFrame(false);
if (result < 0) { gifDecodeFailed = true; return IMAGE_ERROR_FRAME_DECODE; }
if (result < 0) {
gifDecodeFailed = true;
USER_PRINTF("GIF Frame decode failed %d\n", result);
return IMAGE_ERROR_FRAME_DECODE;
}

currentFrameDelay = decoder.getFrameDelay_ms();
unsigned long tooSlowBy = (millis() - lastFrameDisplayTime) - wait; // if last frame was longer than intended, compensate
Expand Down