# HG changeset patch
# User alex@thinkpad
# Date 1367418351 -10800
# Node ID 5189313644e7a57552c5fe64e98ba459eefe98b6
# Parent  ab68b0fa190193b7c1bfcd2119352ae779428a3e
Highlight fix for strong colors when using profile matrix
(well, more like a hack, but works for me)

diff -r ab68b0fa1901 -r 5189313644e7 ufraw_developer.c
--- a/ufraw_developer.c	Thu Dec 12 20:24:57 2013 +0200
+++ b/ufraw_developer.c	Wed May 01 17:25:51 2013 +0300
@@ -617,8 +617,29 @@
         for (c = 0; c < d->colors; c++)
             tmp[cc] += in[c] * d->colorMatrix[cc][c];
     }
+    /**
+     * When color matrix is enabled, there is a bug in highlight recovery and clipping routines
+     * that causes color artifacts (looks like some sort of overflow, not sure).
+     * 
+     * Without color matrix, the image looks perfect even if the RAWs are overexposed.
+     * 
+     * Since I don't understand the highlight recovery algorithm, I'll just apply the color matrix
+     * for midtones and shadows only, and I'll blend it towards the identity matrix as it gets close 
+     * to the clipping point.
+     */
+    
+    int maxin = MAX(MAX(in[0], in[1]), in[2]);
+    
+    /**
+     * at saturation level (65535), it will use identity matrix
+     * at -1EV under saturation level, it will use a 50% blend between color matrix and identity matrix
+     * at -2EV, it will use 75% color matrix and 25% identity
+     * at low EV values (almost the entire luma range), the color matrix will be predominant
+     */
+    double k = MIN(maxin / 65536.0, 1.0);
+    
     for (cc = 0; cc < 3; cc++)
-        out[cc] = MAX(tmp[cc] / 0x10000, 0);
+        out[cc] = MAX((tmp[cc] / 0x10000 * (1-k) + in[cc] * k), 0);
 }
 
 static void cond_apply_matrix(const developer_data *d,