Fix [#20754] Histogram Not Updating, Showing Incorrect Levels, Colour Management on/off leads to Crash

Various internal fixes, also additional feature - can drag on the histogram to change scale 
(0 key to reset).

Also fix [#20844] Color balance node (lift freeze)

1 files changed, 12 insertions, 9 deletions

diff --git a/source/blender/blenkernel/intern/colortools.c b/source/blender/blenkernel/intern/colortools.c
index 7bf147b4906..3c30332b18d 100644
--- a/source/blender/blenkernel/intern/colortools.c
+++ b/source/blender/blenkernel/intern/colortools.c
@@ -882,12 +882,12 @@ void curvemapping_table_RGBA(CurveMapping *cumap, float **array, int *size)
 
 DO_INLINE int get_bin_float(float f)
 {
-	int bin= (int)(f*511);
+	int bin= (int)(f*255);
 
 	/* note: clamp integer instead of float to avoid problems with NaN */
-	CLAMP(bin, 0, 511);
+	CLAMP(bin, 0, 255);
 	
-	//return (int) (((f + 0.25) / 1.5) * 512);
+	//return (int) (((f + 0.25) / 1.5) * 255);
 	
 	return bin;
 }
@@ -903,17 +903,20 @@ void histogram_update(Histogram *hist, ImBuf *ibuf)
 	
 	if (hist->ok == 1 ) return;
 	
+	if (hist->xmax == 0.f) hist->xmax = 1.f;
+	if (hist->ymax == 0.f) hist->ymax = 1.f;
+	
 	/* hmmmm */
 	if (!(ELEM(ibuf->channels, 3, 4))) return;
 	
 	hist->channels = 3;
 	
-	bin_r = MEM_callocN(512 * sizeof(unsigned int), "temp historgram bins");
-	bin_g = MEM_callocN(512 * sizeof(unsigned int), "temp historgram bins");
-	bin_b = MEM_callocN(512 * sizeof(unsigned int), "temp historgram bins");
+	bin_r = MEM_callocN(256 * sizeof(unsigned int), "temp historgram bins");
+	bin_g = MEM_callocN(256 * sizeof(unsigned int), "temp historgram bins");
+	bin_b = MEM_callocN(256 * sizeof(unsigned int), "temp historgram bins");
 	
 	if (ibuf->rect_float) {
-		hist->x_resolution = 512;
+		hist->x_resolution = 256;
 		
 		/* divide into bins */
 		rf = ibuf->rect_float;
@@ -942,7 +945,7 @@ void histogram_update(Histogram *hist, ImBuf *ibuf)
 	
 	/* convert to float */
 	n=0;
-	for (x=0; x<512; x++) {
+	for (x=0; x<256; x++) {
 		if (bin_r[x] > n)
 			n = bin_r[x];
 		if (bin_g[x] > n)
@@ -951,7 +954,7 @@ void histogram_update(Histogram *hist, ImBuf *ibuf)
 			n = bin_b[x];
 	}
 	div = 1.f/(double)n;
-	for (x=0; x<512; x++) {
+	for (x=0; x<256; x++) {
 		hist->data_r[x] = bin_r[x] * div;
 		hist->data_g[x] = bin_g[x] * div;
 		hist->data_b[x] = bin_b[x] * div;