Support for two new CompositeOperation blend modes.

AuburnSounds · Nov 27, 2023 · 5ba098d · 5ba098d
1 parent ea52ce1
commit 5ba098d
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Showing 2 changed files with 95 additions and 2 deletions.
diff --git a/canvas/dplug/canvas/package.d b/canvas/dplug/canvas/package.d
@@ -72,9 +72,16 @@ enum CompositeOperation
 
     /// Add source color (weighted by alpha) to background.
     add,
+    lighter = add,///ditto
 
     /// Subtract source color (weighted by alpha) from background.
-    subtract
+    subtract,
+
+    /// Choose maximum of color values. Do not mistake for "lighter" which is an add, not a max.
+    lighten,
+
+    /// Choose minimum of color values.
+    darken,
 }
 
 
@@ -447,6 +454,8 @@ nothrow:
             case CompositeOperation.sourceOver: op = CompositeOp.SourceOver; break;
             case CompositeOperation.add:        op = CompositeOp.Add; break;
             case CompositeOperation.subtract:   op = CompositeOp.Subtract; break;
+            case CompositeOperation.lighten:    op = CompositeOp.LightenOnly; break;
+            case CompositeOperation.darken:     op = CompositeOp.DarkenOnly; break;
         }
 
         _rasterizer.rasterize(cast(ubyte*) _imageDest.pixels,

diff --git a/canvas/dplug/canvas/rasterizer.d b/canvas/dplug/canvas/rasterizer.d
@@ -85,7 +85,9 @@ enum CompositeOp
 {
     SourceOver,
     Add,
-    Subtract
+    Subtract,
+    LightenOnly,
+    DarkenOnly
 }
 
 /*
@@ -475,6 +477,88 @@ nothrow:
                             _mm_storeu_si128(cast(__m128i*) &dest[x], R);
                         }
                         break;
+
+                    case CompositeOp.LightenOnly:
+                        //    (1 - alpha) * bg + max(bg, fg) * alpha
+                        // == (1 - alpha) * bg + max(bg * alpha, fg * alpha) and we get fg.alpha
+                        for (int x = startx; x < endx; x += 4)
+                        {
+                            __m128i D = _mm_loadu_si128(cast(__m128i*) &dest[x]);   // BG
+                            __m128i S = _mm_loadu_si128(cast(__m128i*) &tmpBuf[x]); // FG * A, A
+                            __m128i Z = _mm_setzero_si128();
+
+                            __m128i D0_1 = _mm_unpacklo_epi8(D, Z); // two background pixels
+                            __m128i D2_3 = _mm_unpackhi_epi8(D, Z); // ditto
+                            __m128i S0_1 = _mm_unpacklo_epi8(S, Z); // two foreground pixels
+                            __m128i S2_3 = _mm_unpackhi_epi8(S, Z); // ditto
+
+                            __m128i A0_1 = _mm_shufflelo_epi16!0xff(_mm_shufflehi_epi16!0xff(S0_1)); // A0 A0 A0 A0 A1 A1 A1 A1
+                            __m128i A2_3 = _mm_shufflelo_epi16!0xff(_mm_shufflehi_epi16!0xff(S2_3)); // A2 A2 A2 A2 A3 A3 A3 A3
+                            __m128i m255 = _mm_set1_epi16(255);
+                            __m128i mA0_1 = _mm_sub_epi16(m255, A0_1); // (255-A0)x4 (255-A1)x4
+                            __m128i mA2_3 = _mm_sub_epi16(m255, A2_3);
+                            A0_1 = _mm_slli_epi16(A0_1, 8);
+                            A2_3 = _mm_slli_epi16(A2_3, 8);
+                            mA0_1 = _mm_slli_epi16(mA0_1, 8);
+                            mA2_3 = _mm_slli_epi16(mA2_3, 8);
+
+                            // multiply bg * alpha
+                            __m128i BGA0_1 = _mm_mulhi_epu16(A0_1, D0_1);
+                            __m128i BGA2_3 = _mm_mulhi_epu16(A2_3, D2_3);
+
+                            // multiply bg * (1 - alpha)
+                            __m128i mBGA0_1 = _mm_mulhi_epu16(mA0_1, D0_1);
+                            __m128i mBGA2_3 = _mm_mulhi_epu16(mA2_3, D2_3);
+
+                            __m128i R0_1 = _mm_add_epi16( _mm_max_epi16(S0_1, BGA0_1), mBGA0_1);
+                            __m128i R2_3 = _mm_add_epi16( _mm_max_epi16(S2_3, BGA2_3), mBGA2_3);
+
+                            __m128i R = _mm_packus_epi16(R0_1, R2_3);
+                            R = _mm_or_si128(R, alphaMask);
+                            _mm_storeu_si128(cast(__m128i*) &dest[x], R);
+                        }
+                        break;
+
+                    case CompositeOp.DarkenOnly:
+                        //    (1 - alpha) * bg + min(bg, fg) * alpha
+                        // == (1 - alpha) * bg + min(bg * alpha, fg * alpha) and we get fg.alpha
+                        for (int x = startx; x < endx; x += 4)
+                        {
+                            __m128i D = _mm_loadu_si128(cast(__m128i*) &dest[x]);   // BG
+                            __m128i S = _mm_loadu_si128(cast(__m128i*) &tmpBuf[x]); // FG * A, A
+                            __m128i Z = _mm_setzero_si128();
+
+                            __m128i D0_1 = _mm_unpacklo_epi8(D, Z); // two background pixels
+                            __m128i D2_3 = _mm_unpackhi_epi8(D, Z); // ditto
+                            __m128i S0_1 = _mm_unpacklo_epi8(S, Z); // two foreground pixels
+                            __m128i S2_3 = _mm_unpackhi_epi8(S, Z); // ditto
+
+                            __m128i A0_1 = _mm_shufflelo_epi16!0xff(_mm_shufflehi_epi16!0xff(S0_1)); // A0 A0 A0 A0 A1 A1 A1 A1
+                            __m128i A2_3 = _mm_shufflelo_epi16!0xff(_mm_shufflehi_epi16!0xff(S2_3)); // A2 A2 A2 A2 A3 A3 A3 A3
+                            __m128i m255 = _mm_set1_epi16(255);
+                            __m128i mA0_1 = _mm_sub_epi16(m255, A0_1); // (255-A0)x4 (255-A1)x4
+                            __m128i mA2_3 = _mm_sub_epi16(m255, A2_3);
+                            A0_1 = _mm_slli_epi16(A0_1, 8);
+                            A2_3 = _mm_slli_epi16(A2_3, 8);
+                            mA0_1 = _mm_slli_epi16(mA0_1, 8);
+                            mA2_3 = _mm_slli_epi16(mA2_3, 8);
+
+                            // multiply bg * alpha
+                            __m128i BGA0_1 = _mm_mulhi_epu16(A0_1, D0_1);
+                            __m128i BGA2_3 = _mm_mulhi_epu16(A2_3, D2_3);
+
+                            // multiply bg * (1 - alpha)
+                            __m128i mBGA0_1 = _mm_mulhi_epu16(mA0_1, D0_1);
+                            __m128i mBGA2_3 = _mm_mulhi_epu16(mA2_3, D2_3);
+
+                            __m128i R0_1 = _mm_add_epi16( _mm_min_epi16(S0_1, BGA0_1), mBGA0_1);
+                            __m128i R2_3 = _mm_add_epi16( _mm_min_epi16(S2_3, BGA2_3), mBGA2_3);
+
+                            __m128i R = _mm_packus_epi16(R0_1, R2_3);
+                            R = _mm_or_si128(R, alphaMask);
+                            _mm_storeu_si128(cast(__m128i*) &dest[x], R);
+                        }
+                        break;
                 }
             }