Fix the incorrect kernel size in Stack Blur

The valid kernel size range is from 1 to 15.

Signed-off-by: Wei-Hsin Yeh <[email protected]>

Author: weihsinyeh

apps/multi.c

@@ -304,8 +304,11 @@ static void apps_blur(twin_screen_t *screen, int x, int y, int w, int h)
     twin_composite(scaled_background, 0, 0, &srcop, 0, 0, 0, 0, 0, TWIN_SOURCE,
                    scaled_background->width, scaled_background->height);
 
-    /* Apply blur effect to the scaled background */
-    twin_stack_blur(scaled_background, 16, 0, scaled_background->width - 1, 0,
+    /*
+     * Apply blur effect to the scaled background. The valid kernel size range
+     * is from 1 to 15.
+     */
+    twin_stack_blur(scaled_background, 15, 0, scaled_background->width - 1, 0,
                     scaled_background->height - 1);
 
     /* Copy the blurred background to the window */

configs/Kconfig

@@ -74,7 +74,7 @@ config VERTICAL_OFFSET
 config SHADOW_BLUR
     int "Shadow blur radius"
     default 10
-    range 1 10
+    range 1 15
     depends on DROP_SHADOW
 
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