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). test/jdk/javax/imageio/plugins/bmp/RLE4PaddingTest.java line 32: > 30: */ > 31: > 32: import javax.imageio.IIOImage; Maybe `import javax.*` looks better after `import java.*` test/jdk/javax/imageio/plugins/bmp/RLE4PaddingTest.java line 44: > 42: > 43: public class RLE4PaddingTest { > 44: static int width = 5; The `width` and `height` can be modified as `private static final` ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/31447#discussion_r3388299821 PR Review Comment: https://git.openjdk.org/jdk/pull/31447#discussion_r3388291271
