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tilman pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/pdfbox-jbig2.git
The following commit(s) were added to refs/heads/master by this push:
new 97935ae PDFBOX-6156: fix setPixel
97935ae is described below
commit 97935ae1a0c9d11b068671035ace4862a9bf0711
Author: Tilman Hausherr <[email protected]>
AuthorDate: Thu Jan 29 16:40:57 2026 +0100
PDFBOX-6156: fix setPixel
---
src/main/java/org/apache/pdfbox/jbig2/Bitmap.java | 20 ++++++++++++++++++--
.../java/org/apache/pdfbox/jbig2/BitmapTest.java | 4 ++++
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/src/main/java/org/apache/pdfbox/jbig2/Bitmap.java
b/src/main/java/org/apache/pdfbox/jbig2/Bitmap.java
index 7784285..0968b65 100644
--- a/src/main/java/org/apache/pdfbox/jbig2/Bitmap.java
+++ b/src/main/java/org/apache/pdfbox/jbig2/Bitmap.java
@@ -75,6 +75,16 @@ public class Bitmap
return (byte) ((this.getByte(byteIndex) >> toShift) & 0x01);
}
+ /**
+ * Sets the value of a pixel specified by the given coordinates.
+ * <p>
+ * By default, the value is {@code 0} for a white pixel and {@code 1} for
a black pixel. The
+ * value is taken from the rightmost bit in the byte.
+ *
+ * @param x - The x coordinate of the pixel.
+ * @param y - The y coordinate of the pixel.
+ * @param pixelValue The value of a pixel.
+ */
public void setPixel(int x, int y, byte pixelValue)
{
final int byteIndex = getByteIndex(x, y);
@@ -83,8 +93,14 @@ public class Bitmap
final int shift = 7 - bitOffset;
final byte src = bitmap[byteIndex];
- final byte result = (byte) (src | (pixelValue << shift));
- bitmap[byteIndex] = result;
+ if ((pixelValue & 1) == 1)
+ {
+ bitmap[byteIndex] = (byte) (src | (1 << shift));
+ }
+ else
+ {
+ bitmap[byteIndex] = (byte) (src & ~(1 << shift));
+ }
}
/**
diff --git a/src/test/java/org/apache/pdfbox/jbig2/BitmapTest.java
b/src/test/java/org/apache/pdfbox/jbig2/BitmapTest.java
index 1728f65..b505ddd 100644
--- a/src/test/java/org/apache/pdfbox/jbig2/BitmapTest.java
+++ b/src/test/java/org/apache/pdfbox/jbig2/BitmapTest.java
@@ -34,6 +34,10 @@ public class BitmapTest
bitmap.setPixel(3, 19, (byte) 1);
assertEquals(1, bitmap.getPixel(3, 19));
+
+ bitmap.setPixel(3, 19, (byte) 0);
+
+ assertEquals(0, bitmap.getPixel(3, 19));
}
@Test
