Changeset 1104

Timestamp:

03/26/11 21:40:07 (2 years ago)

Author:

reyalP

Message:

histogram fixes from philmoz in ​http://chdk.setepontos.com/index.php?topic=650.msg63231#msg63231

File:

• trunk/core/histogram.c (modified) (5 diffs)

trunk/core/histogram.c

@@ -61 +61 @@
 }
 
+// Define how many viewport blocks to step in each loop iteration. Each block is 6 bytes (UYVYYY) or 4 image pixels
+#define HISTO_STEP_SIZE 6
+
 void histogram_process()
 {
@@ -66 +69 @@
     int i, hi, c;
     int y, v, u;
-        static int x, img_offset;
+        static int x;
     static int viewport_size;
     unsigned int histo_fill[5];
@@ -77 +80 @@
                   img = vid_get_viewport_fb();
                     }
-                        img_offset = vid_get_viewport_image_offset();           // offset into viewport for when image size != viewport size (e.g. 16:9 image on 4:3 LCD)
+                        img += vid_get_viewport_image_offset();         // offset into viewport for when image size != viewport size (e.g. 16:9 image on 4:3 LCD)
             viewport_size = vid_get_viewport_height() * vid_get_viewport_buffer_width();
             for (c=0; c<5; ++c) {
@@ -92 +95 @@
         case 2:
         case 3:
-                        x = 0;
-            for (i=(histogram_stage-1)*6; i<viewport_size*3; i+=6*3*2) {
-                y = img[img_offset+i+1];
-                u = *(signed char*)(&img[img_offset+i]);
+                        x = 0;  // count how many blocks we have done on the current row (to skip unused buffer space at end of each row)
+            for (i=(histogram_stage-1)*6; i<viewport_size*3; i+=HISTO_STEP_SIZE*6) {
+                y = img[i+1];
+                u = *(signed char*)(&img[i]);
                 if (u&0x00000080) u|=0xFFFFFF00;
-                v = *(signed char*)(&img[img_offset+i+2]);
+                v = *(signed char*)(&img[i+2]);
                 if (v&0x00000080) v|=0xFFFFFF00;
 
@@ -110 +113 @@
 
                                 // Handle case where viewport memory buffer is wider than the actual buffer.
-                                x++;
+                                x += HISTO_STEP_SIZE * 2;       // viewport width is measured in blocks of three bytes each even though the data is stored in six byte chunks !
                                 if (x == vid_get_viewport_width())
                                 {