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Better PFM support.

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(cherry picked from commit 623d13a517)
This commit is contained in:
Harald Kuhr
2020-09-25 19:35:55 +02:00
committed by Harald Kuhr
parent 15c7cfe9a6
commit 75ff0f265f
4 changed files with 45 additions and 37 deletions
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17
imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java
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@@ -291,4 +291,21 @@ public final class IIOUtil {
System.arraycopy(srcRow, srcPos + x, destRow, destPos + x / samplePeriod, pixelStride);
}
}
public static void subsampleRow(float[] srcRow, int srcPos, int srcWidth,
float[] destRow, int destPos,
int samplesPerPixel, int bitsPerSample, int samplePeriod) {
Validate.isTrue(samplePeriod > 1, "samplePeriod must be > 1"); // Period == 1 could be a no-op...
Validate.isTrue(bitsPerSample > 0 && bitsPerSample <= 32 && (bitsPerSample == 1 || bitsPerSample % 2 == 0),
"bitsPerSample must be > 0 and <= 32 and a power of 2");
Validate.isTrue(samplesPerPixel > 0, "samplesPerPixel must be > 0");
Validate.isTrue(samplesPerPixel * bitsPerSample <= 32 || samplesPerPixel * bitsPerSample % 32 == 0,
"samplesPerPixel * bitsPerSample must be < 32 or a multiple of 32 ");
int pixelStride = bitsPerSample * samplesPerPixel / 32;
for (int x = 0; x < srcWidth * pixelStride; x += samplePeriod * pixelStride) {
// System.arraycopy should be intrinsic, but consider using direct array access for pixelStride == 1
System.arraycopy(srcRow, srcPos + x, destRow, destPos + x / samplePeriod, pixelStride);
}
}
}