CPC_compare_colors()

used in Save_SCR()

src/miscfileformats.c

@@ -4213,7 +4213,7 @@ void Save_SCR(T_IO_Context * context)
     // search for the color in the HW palette (0x40-0x5F)
     byte index = 0x40;
     while ((index < 0x60) &&
-        (0 != memcmp(context->Palette + i, context->Palette + index, sizeof(T_Components))))
+        !CPC_compare_colors(context->Palette + i, context->Palette + index))
       index++;
     if (index >= 0x60)
     {

src/oldies.c

@@ -504,6 +504,18 @@ void CPC_set_HW_palette(T_Components * palette)
   memcpy(palette, CPC_Hw_Palette, sizeof(CPC_Hw_Palette));
 }
 
+int CPC_compare_colors(T_Components * col1, T_Components * col2)
+{
+  byte v1, v2;
+  /** The mapping used in this function is :
+   * - RGB value   [0: 85] => CPC level 0
+   * - RGB value  [86:171] => CPC level 1
+   * - RGB value [172:255] => CPC level 2 */
+  v1 = (col1->R / 86) << 4 | (col1->G / 86) << 2 | (col1->B / 86);
+  v2 = (col2->R / 86) << 4 | (col2->G / 86) << 2 | (col2->B / 86);
+  return v1 == v2;
+}
+
 void CPC_set_default_BASIC_palette(T_Components * palette)
 {
   static const byte basic_colors[] = {
@@ -513,6 +525,10 @@ void CPC_set_default_BASIC_palette(T_Components * palette)
     0x52, 0x59, 0x4a, 0x47
   };
   unsigned int i;
+  /** in the default CPC Basic palette, INKs 14 and 15 are blicking,
+   * so that would be great to include theses in the colorcycling,
+   * but I don't see any way to make theses blinking colors
+   * with the way GrafX2 handles color cycling */
 
   for (i = 0; i < sizeof(basic_colors) / sizeof(byte); i++)
     memcpy(palette + i,

src/oldies.h

@@ -80,6 +80,17 @@ void CPC_set_HW_palette(T_Components * palette);
  */
 void CPC_set_default_BASIC_palette(T_Components * palette);
 
+/**
+ * compare two RGB colors
+ *
+ * The RGB colors are compared in order as if they were
+ * converted from CPC (27 color palette), as there are several
+ * mapping of the 3 level CPC RGB signals.
+ *
+ * @return true if the RGB colors map to the same CPC color
+ */
+int CPC_compare_colors(T_Components * col1, T_Components * col2);
+
 /**
  * Check AMSDOS header
  *