Add thresholding image functions.

daid · Sep 30, 2023 · 582dc3e · 582dc3e
1 parent b7f409b
commit 582dc3e
Showing 1 changed file with 42 additions and 0 deletions.
diff --git a/include/sp2/graphics/image/threshold.h b/include/sp2/graphics/image/threshold.h
@@ -0,0 +1,42 @@
+#ifndef SP2_GRAPHICS_IMAGE_THRESHOLD_H
+#define SP2_GRAPHICS_IMAGE_THRESHOLD_H
+
+#include <sp2/graphics/image.h>
+
+
+namespace sp::image {
+
+static inline sp::Image8 threshold(const sp::Image8& input, int threshold_value, int neg=0, int pos=255) {
+    sp::Image8 output{input.getSize()};
+    auto ptr_i = input.getPtr();
+    auto ptr_o = output.getPtr();
+    for(auto n=0; n<input.getSize().x*input.getSize().y;n++) {
+        if (*ptr_i >= threshold_value)
+            *ptr_o = pos;
+        else
+            *ptr_o = neg;
+        ptr_i++;
+        ptr_o++;
+    }
+    return output;
+}
+
+static inline sp::Image8 adaptiveThreshold(const sp::Image8& input, int blocksize, int offset, int neg=0, int pos=255) {
+    auto output = sp::image::gaussianBlur(input, blocksize);
+    auto ptr_i = input.getPtr();
+    auto ptr_o = output.getPtr();
+    for(auto n=0; n<input.getSize().x*input.getSize().y;n++) {
+        if (*ptr_i > *ptr_o + offset)
+            *ptr_o = pos;
+        else
+            *ptr_o = neg;
+        ptr_i++;
+        ptr_o++;
+    }
+    return output;
+}
+
+}//namespace sp::image
+
+
+#endif//SP2_GRAPHICS_IMAGE_THRESHOLD_H