Fix sample spacing in lens shading map saved to DNG
We were using an incorrect sample spacing of 1/N instead of 1/(N-1). This affected rendering in 3rd party tools like Adobe Photoshop, effectively shrinking the lens shading map and replicating values from the bottom-most row and right-most column.
Bug: 77657628
Test: created test pattern lens shading maps, loaded DNG in Photoshop
Change-Id: Ia814ebefeceafc72b17058a9c4cf598140d3f752
diff --git a/media/img_utils/src/DngUtils.cpp b/media/img_utils/src/DngUtils.cpp
index 9dc5f05..67ec244 100644
--- a/media/img_utils/src/DngUtils.cpp
+++ b/media/img_utils/src/DngUtils.cpp
@@ -18,6 +18,7 @@
#include <inttypes.h>
+#include <algorithm>
#include <vector>
#include <math.h>
@@ -61,8 +62,8 @@
const float* lensShadingMap) {
uint32_t activeAreaWidth = activeAreaRight - activeAreaLeft;
uint32_t activeAreaHeight = activeAreaBottom - activeAreaTop;
- double spacingV = 1.0 / lsmHeight;
- double spacingH = 1.0 / lsmWidth;
+ double spacingV = 1.0 / std::max(1u, lsmHeight - 1);
+ double spacingH = 1.0 / std::max(1u, lsmWidth - 1);
std::vector<float> redMapVector(lsmWidth * lsmHeight);
float *redMap = redMapVector.data();