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The following commit(s) were added to refs/heads/geoapi-4.0 by this push:
new 8c9c31766b Fix: calculation of contributions in `ImageOverlay` was too
large. Edit documentation by saying that each image is fully opaque.
8c9c31766b is described below
commit 8c9c31766bcde90d64a7372137b59c6e1a66c78d
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Sat Dec 21 21:54:54 2024 +0100
Fix: calculation of contributions in `ImageOverlay` was too large.
Edit documentation by saying that each image is fully opaque.
---
.../main/org/apache/sis/image/ImageOverlay.java | 16 ++++++++--------
.../main/org/apache/sis/image/ImageProcessor.java | 14 +++++++++-----
2 files changed, 17 insertions(+), 13 deletions(-)
diff --git
a/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageOverlay.java
b/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageOverlay.java
index c7f13c83fe..4bb06de124 100644
---
a/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageOverlay.java
+++
b/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageOverlay.java
@@ -48,7 +48,9 @@ import org.apache.sis.coverage.privy.ImageUtilities;
* An overlay of an arbitrary number of images. All images have the same pixel
coordinate system,
* but potentially different bounding boxes, tile sizes and tile indices.
Source images are drawn
* in reverse order: the last source image is drawn first, and the first
source image is drawn last
- * on top of all other images. The requirements are:
+ * on top of all other images. All images are considered fully opaque,
including the alpha channel
+ * which is handled as an ordinary band.
+ * The requirements are:
*
* <ul>
* <li>All source images shall have the same pixel coordinate systems (but
not necessarily the same tile matrix).</li>
@@ -120,12 +122,11 @@ final class ImageOverlay extends MultiSourceImage {
final Area area = new Area(ImageUtilities.getValidArea(source));
if (aoi != null) area.intersect(aoi);
if (area.isEmpty()) continue; // Source does not intersect
the specified bounds.
+ final Area contrib = new Area(area);
+ contrib.subtract(validArea);
+ if (contrib.isEmpty()) continue; // The new source is fully
masked by previous sources.
validArea.add(area);
- if (count != 0) {
- area.subtract(contributions[count - 1]);
- if (area.isEmpty()) continue; // The new source is fully
masked by previous sources.
- }
- contributions[count] = area;
+ contributions[count] = contrib;
sources[count++] = source;
/*
* The default sample model is selected after filtering because
the choice of a sample model
@@ -160,8 +161,7 @@ final class ImageOverlay extends MultiSourceImage {
sources = ArraysExt.resize(sources, count);
contributions = ArraysExt.resize(contributions, count);
/*
- * Last area is now the union of the Area Of iInterest (AOI) of all
source images.
- * The size of the destination image is this valid area, unless
specified otherwise.
+ * The valid area defines the size of the combined image, unless
specified otherwise.
* If the tile size is not a divisor of the image size, try to find a
better tile size.
*/
if (bounds == null) {
diff --git
a/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageProcessor.java
b/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageProcessor.java
index db2faaefa2..59e1ea80dd 100644
---
a/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageProcessor.java
+++
b/endorsed/src/org.apache.sis.feature/main/org/apache/sis/image/ImageProcessor.java
@@ -969,13 +969,17 @@ public class ImageProcessor implements Cloneable {
* Creates a new image overlay or returns one of the given sources if
equivalent.
* All source images shall have the same pixel coordinate system, but they
may have different bounding boxes,
* tile sizes and tile indices. Images are drawn in reverse order: the
last source image is drawn first, and
- * the first source image is drawn last on top of all other images. The
returned image may have less sources
- * than the specified ones if this method determines that some sources
will never be drawn.
- * This method may return {@code sources[0]} directly.
+ * the first source image is drawn last on top of all other images. All
images are considered fully opaque,
+ * including the alpha channel which is handled as an ordinary band.
*
- * <p>All source images shall have the same number of bands (but not
necessarily the same sample model).
+ * <p>The returned image may have less sources than the ones given in
argument if this method determines
+ * that some sources will never be drawn (i.e., are fully hidden behind
the first images).
+ * If only one source appears to be effectively used, this method returns
that image directly.</p>
+ *
+ * <h4>Preconditions</h4>
+ * All source images shall have the same number of bands (but not
necessarily the same sample model).
* All source images should have equivalent color model, otherwise color
consistency is not guaranteed.
- * At least one image shall intersect the given bounds.</p>
+ * At least one image shall intersect the given bounds.
*
* <h4>Properties used</h4>
* This operation uses the following properties in addition to method
parameters:
