Fixed mismatched banner and background

There was an issue with loss of color precision. Saturation dropped to zero when converting to 8-bit RGB.

3 files changed, 7 insertions, 5 deletions

diff --git a/src/gmdocument.c b/src/gmdocument.c
index bc0cc073..79deb861 100644
--- a/src/gmdocument.c
+++ b/src/gmdocument.c
@@ -1569,7 +1569,7 @@ void setThemeSeed_GmDocument(iGmDocument *d, const iBlock *paletteSeed, const iB
 
         if (theme == colorfulDark_GmDocumentTheme) {
             iHSLColor base    = { hues[primIndex],
-                                  0.8f * (d->themeSeed >> 24) / 255.0f,
+                                  0.8f * (d->themeSeed >> 24) / 255.0f + minSat_HSLColor,
                                   0.06f + 0.09f * ((d->themeSeed >> 5) & 0x7) / 7.0f,
                                   1.0f };
             iHSLColor altBase = { altHue, base.sat, base.lum, 1 };
@@ -1579,13 +1579,13 @@ void setThemeSeed_GmDocument(iGmDocument *d, const iBlock *paletteSeed, const iB
             setHsl_Color(tmBannerBackground_ColorId, addSatLum_HSLColor(base, 0.1f, 0.04f * (isBannerLighter ? 1 : -1)));
             setHsl_Color(tmBannerTitle_ColorId, setLum_HSLColor(addSatLum_HSLColor(base, 0.1f, 0), 0.55f));
             setHsl_Color(tmBannerIcon_ColorId, setLum_HSLColor(addSatLum_HSLColor(base, 0.35f, 0), 0.65f));
-
+            
 //            printf("primHue: %zu  alts: %d %d  isDarkBgSat: %d\n",
 //                   primIndex,
 //                   altHues[primIndex].index[altIndex[0]],
 //                   altHues[primIndex].index[altIndex[1]],
 //                   isDarkBgSat);
-
+            
             const float titleLum = 0.2f * ((d->themeSeed >> 17) & 0x7) / 7.0f;
             setHsl_Color(tmHeading1_ColorId, setLum_HSLColor(altBase, titleLum + 0.80f));
             setHsl_Color(tmHeading2_ColorId, setLum_HSLColor(altBase, titleLum + 0.70f));
diff --git a/src/ui/color.c b/src/ui/color.c
index 824342ae..9cba322d 100644
--- a/src/ui/color.c
+++ b/src/ui/color.c
@@ -522,8 +522,8 @@ iHSLColor setLum_HSLColor(iHSLColor d, float lum) {
 }
 
 iHSLColor addSatLum_HSLColor(iHSLColor d, float sat, float lum) {
-    d.sat = iClamp(d.sat + sat, 0, 1);
-    d.lum = iClamp(d.lum + lum, 0, 1);
+    d.sat = iClamp(d.sat + sat, minSat_HSLColor, 1);
+    d.lum = iClamp(d.lum + lum, minSat_HSLColor, 1);
     return d;
 }
 
diff --git a/src/ui/color.h b/src/ui/color.h
index 24f9e713..f46976d7 100644
--- a/src/ui/color.h
+++ b/src/ui/color.h
@@ -231,6 +231,8 @@ struct Impl_HSLColor {
     float hue, sat, lum, a;
 };
 
+#define minSat_HSLColor 0.013f   /* Conversion to 8-bit RGB may result in saturation dropping to zero. */
+
 iHSLColor       hsl_Color       (iColor);
 iColor          rgb_HSLColor    (iHSLColor);
 float           luma_Color      (iColor);