C API: add sk_xfermode.h, impl, test

src/c/sk_paint.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "sk_paint.h"
 #include "sk_types_priv.h"
 
@@ skipping 114 matching lines @@
 
 void sk_paint_set_stroke_join(sk_paint_t* cpaint, sk_stroke_join_t cjoin) {
     SkPaint::Join skjoin;
     if (find_sk(cjoin, &skjoin)) {
         AsPaint(cpaint)->setStrokeJoin(skjoin);
     } else {
         // unknown cjoin
     }
 }
 
-
+void sk_paint_set_xfermode_mode(sk_paint_t* paint, sk_xfermode_mode_t mode) {
+    SkASSERT(paint);

[reed1, 2015/07/31 18:15:31]

don't need this, as the setXfermode will reliably crash

+    SkXfermode::Mode skmode = SkXfermode::Mode(-1);
+    switch (mode) {
+        #define MAP(X, Y) case (X): skmode = (Y); break
+        MAP( CLEAR_SK_XFERMODE_MODE,      SkXfermode::kClear_Mode      );
+        MAP( SRC_SK_XFERMODE_MODE,        SkXfermode::kSrc_Mode        );
+        MAP( DST_SK_XFERMODE_MODE,        SkXfermode::kDst_Mode        );
+        MAP( SRCOVER_SK_XFERMODE_MODE,    SkXfermode::kSrcOver_Mode    );
+        MAP( DSTOVER_SK_XFERMODE_MODE,    SkXfermode::kDstOver_Mode    );
+        MAP( SRCIN_SK_XFERMODE_MODE,      SkXfermode::kSrcIn_Mode      );
+        MAP( DSTIN_SK_XFERMODE_MODE,      SkXfermode::kDstIn_Mode      );
+        MAP( SRCOUT_SK_XFERMODE_MODE,     SkXfermode::kSrcOut_Mode     );
+        MAP( DSTOUT_SK_XFERMODE_MODE,     SkXfermode::kDstOut_Mode     );
+        MAP( SRCATOP_SK_XFERMODE_MODE,    SkXfermode::kSrcATop_Mode    );
+        MAP( DSTATOP_SK_XFERMODE_MODE,    SkXfermode::kDstATop_Mode    );
+        MAP( XOR_SK_XFERMODE_MODE,        SkXfermode::kXor_Mode        );
+        MAP( PLUS_SK_XFERMODE_MODE,       SkXfermode::kPlus_Mode       );
+        MAP( MODULATE_SK_XFERMODE_MODE,   SkXfermode::kModulate_Mode   );
+        MAP( SCREEN_SK_XFERMODE_MODE,     SkXfermode::kScreen_Mode     );
+        MAP( OVERLAY_SK_XFERMODE_MODE,    SkXfermode::kOverlay_Mode    );
+        MAP( DARKEN_SK_XFERMODE_MODE,     SkXfermode::kDarken_Mode     );
+        MAP( LIGHTEN_SK_XFERMODE_MODE,    SkXfermode::kLighten_Mode    );
+        MAP( COLORDODGE_SK_XFERMODE_MODE, SkXfermode::kColorDodge_Mode );
+        MAP( COLORBURN_SK_XFERMODE_MODE,  SkXfermode::kColorBurn_Mode  );
+        MAP( HARDLIGHT_SK_XFERMODE_MODE,  SkXfermode::kHardLight_Mode  );
+        MAP( SOFTLIGHT_SK_XFERMODE_MODE,  SkXfermode::kSoftLight_Mode  );
+        MAP( DIFFERENCE_SK_XFERMODE_MODE, SkXfermode::kDifference_Mode );
+        MAP( EXCLUSION_SK_XFERMODE_MODE,  SkXfermode::kExclusion_Mode  );
+        MAP( MULTIPLY_SK_XFERMODE_MODE,   SkXfermode::kMultiply_Mode   );
+        MAP( HUE_SK_XFERMODE_MODE,        SkXfermode::kHue_Mode        );
+        MAP( SATURATION_SK_XFERMODE_MODE, SkXfermode::kSaturation_Mode );
+        MAP( COLOR_SK_XFERMODE_MODE,      SkXfermode::kColor_Mode      );
+        MAP( LUMINOSITY_SK_XFERMODE_MODE, SkXfermode::kLuminosity_Mode );
+        #undef MAP
+    }
+    SkASSERT((int)skmode != -1);
+    AsPaint(paint)->setXfermodeMode(skmode);
+}