Fix bugs in GIF decoding #26738
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this is related to #25691
i solved two bugs here:
1. the decoding setting:
according to [https://www.w3.org/Graphics/GIF/spec-gif89a.txt](https://www.w3.org/Graphics/GIF/spec-gif89a.txt)
```
DEFERRED CLEAR CODE IN LZW COMPRESSION
There has been confusion about where clear codes can be found in the
data stream. As the specification says, they may appear at anytime. There
is not a requirement to send a clear code when the string table is full.
It is the encoder's decision as to when the table should be cleared. When
the table is full, the encoder can chose to use the table as is, making no
changes to it until the encoder chooses to clear it. The encoder during
this time sends out codes that are of the maximum Code Size.
As we can see from the above, when the decoder's table is full, it must
not change the table until a clear code is received. The Code Size is that
of the maximum Code Size. Processing other than this is done normally.
Because of a large base of decoders that do not handle the decompression in
this manner, we ask developers of GIF encoding software to NOT implement
this feature until at least January 1991 and later if they see that their
particular market is not ready for it. This will give developers of GIF
decoding software time to implement this feature and to get it into the
hands of their clients before the decoders start "breaking" on the new
GIF's. It is not required that encoders change their software to take
advantage of the deferred clear code, but it is for decoders.
```
at first i didn't consider this case, thus leads to a bug discussed in #25691. the changes made in function lzwDecode() is aiming at solving this.
2. the fetch method of loopCount:
in the codes at https://github.com/opencv/opencv/blob/4.x/modules/imgcodecs/src/grfmt_gif.cpp#L410, if the branch is taken, 3 more bytes will be taken, leading to unpredictable behavior.
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Add more boundary checks. #26739
Also fix a bug in read_chunk where we could end up with png_get_uint_32(len) + 12 < 4
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Fix for png durations and memory leak #26714
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Fix leaks in cv::PngDecoder #26701
Bug: oss-fuzz:386688709
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Animated PNG Support #25715
Continues https://github.com/opencv/opencv/pull/25608
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Animated WebP Support #25608
related issues #24855#22569
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[GSoC] Add GIF decode and encode for imgcodecs #25691
this is related to #24855
we add gif support for `imread`, `imreadmulti`, `imwrite` and `imwritemulti`
opencv_extra: https://github.com/opencv/opencv_extra/pull/1203
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imgcodecs: implement imencodemulti() #26211Close#26207
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Proposed solution for the issue 26297 #26298closes#26297
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Documentation update for imagecodecs #26152
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Update test_tiff.cpp #26093
related #22090
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code clean #25931
Align code and remove redundant CMake code
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Make sure all the lines of a JPEG are read #25864
In case of corrupted JPEG, imread would still return a JPEG of the proper size (as indicated by the header) but with some uninitialized values. I do not have a short reproducer I can add as a test as this was found by our fuzzers.
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imgcodecs: Add rgb flag for imread and imdecode #25809
Try to `imread` images by RGB to save R-B swapping costs.
## How to use it?
```
img_rgb = cv2.imread("PATH", IMREAD_COLOR_RGB) # OpenCV decode the image by RGB format.
```
## TODO
- [x] Fix the broken code
- [x] Add imread rgb test
- [x] Speed test of rgb mode.
## Performance test
| file name | IMREAD_COLOR | IMREAD_COLOR_RGB |
| --------- | ------ | --------- |
| jpg01 | 284 ms | 277 ms |
| jpg02 | 376 ms | 366 ms |
| png01 | 62 ms | 60 ms |
| Png02 | 97 ms | 94 ms |
Test with [image_test.zip](https://github.com/user-attachments/files/15982949/image_test.zip)
```.cpp
string img_path = "/Users/mzh/work/data/image_test/png02.png";
int loop = 20;
TickMeter t;
double t0 = 10000;
for (int i = 0; i < loop; i++)
{
t.reset();
t.start();
img_bgr = imread(img_path, IMREAD_COLOR);
t.stop();
if (t.getTimeMilli() < t0) t0 = t.getTimeMilli();
}
std::cout<<"bgr time = "<<t0<<std::endl;
t0 = 10000;
for (int i = 0; i < loop; i++)
{
t.reset();
t.start();
img_rgb = imread(img_path, IMREAD_COLOR_RGB);
t.stop();
if (t.getTimeMilli() < t0) t0 = t.getTimeMilli();
}
std::cout<<"rgb time = "<<t0<<std::endl;
```
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imgcodecs: support IMWRITE_JPEG_LUMA/CHROMA_QUALITY with internal libjpeg-turbo #25647Close#25646
- increase JPEG_LIB_VERSION for internal libjpeg-turbo from 62 to 70
- add log when using IMWRITE_JPEG_LUMA/CHROMA_QUALITY with JPEG_LIB_VERSION<70
- add document IMWRITE_JPEG_LUMA/CHROMA_QUALITY requests JPEG_LIB_VERSION >= 70
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Vincent Rabaud
Super
Alexander Smorkalov
Alexander Smorkalov
Suleyman TURKMEN
Alexander Smorkalov
Kumataro
cDc
Letu Ren
Maksim Shabunin
xkszltl
zihaomu
Sourav Kumar
Mikhail Khachayants