On Wed, 10 Jun 2026 05:15:16 GMT, Jayathirth D V <[email protected]> wrote:

> We use `Math.ceil()` at 2 places in BMPImageWriter and both of them are under 
> encodeRLE4() function. Also they are used only under absolute mode of 
> encoding.
> 
> First usage `(int)Math.ceil((absVal-1)/2)` is while encoding data in each 
> scanline. Here absVal always starts with 3 and increments by 2, so 
> `Math.ceil()` is basically a no-op here and its usage can be removed.
> 
> Second usage `(int)Math.ceil((absVal+1)/2)` is while encoding end of scanline 
> data. Here absVal can be even and we need to use `Math.ceil()` properly 
> otherwise padding will not be added properly. I have added regression test 
> which actually identifies this issue and it creates a corrupt encoded BMP 
> image. In this regression test we have odd number of distinct pixels at the 
> end of scanline and encoding without proper padding corrupts next scanline of 
> data.
> 
> ---------
> - [x] I confirm that I make this contribution in accordance with the [OpenJDK 
> Interim AI Policy](https://openjdk.org/legal/ai).

src/java.desktop/share/classes/com/sun/imageio/plugins/bmp/BMPImageWriter.java 
line 1111:

> 1109:                         q = absBuf[absVal-2] << 4| 0;
> 1110:                         stream.writeByte(q);
> 1111:                         incCompImageSize(1);

Do we need update the copyright year.

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PR Review Comment: https://git.openjdk.org/jdk/pull/31447#discussion_r3388267228

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