Optimize Blend composites.

Removed redundant array allocations to improve performance for various
blending modes.

Change-Id: Iaba1d6ff3ad03eebdc859c599b610cc593370438
(cherry picked from commit 9ce074610413ce3a5dd0cef9295f0ae9061402b7)

1 files changed, 136 insertions, 147 deletions

diff --git a/tools/layoutlib/bridge/src/android/graphics/BlendComposite.java b/tools/layoutlib/bridge/src/android/graphics/BlendComposite.java
index a864f84..a3ec2cc 100644
--- a/tools/layoutlib/bridge/src/android/graphics/BlendComposite.java
+++ b/tools/layoutlib/bridge/src/android/graphics/BlendComposite.java
@@ -197,42 +197,54 @@ public final class BlendComposite implements Composite {
 
             int[] srcPixel = new int[4];
             int[] dstPixel = new int[4];
+            int[] result = new int[4];
             int[] srcPixels = new int[width];
             int[] dstPixels = new int[width];
 
             for (int y = 0; y < height; y++) {
-                src.getDataElements(0, y, width, 1, srcPixels);
                 dstIn.getDataElements(0, y, width, 1, dstPixels);
-                for (int x = 0; x < width; x++) {
-                    // pixels are stored as INT_ARGB
-                    // our arrays are [R, G, B, A]
-                    int pixel = srcPixels[x];
-                    srcPixel[0] = (pixel >> 16) & 0xFF;
-                    srcPixel[1] = (pixel >>  8) & 0xFF;
-                    srcPixel[2] = (pixel      ) & 0xFF;
-                    srcPixel[3] = (pixel >> 24) & 0xFF;
-
-                    pixel = dstPixels[x];
-                    dstPixel[0] = (pixel >> 16) & 0xFF;
-                    dstPixel[1] = (pixel >>  8) & 0xFF;
-                    dstPixel[2] = (pixel      ) & 0xFF;
-                    dstPixel[3] = (pixel >> 24) & 0xFF;
-
-                    int[] result = blender.blend(srcPixel, dstPixel);
-
-                    // mixes the result with the opacity
-                    dstPixels[x] = ((int) (dstPixel[3] + (result[3] - dstPixel[3]) * alpha) & 0xFF) << 24 |
-                                   ((int) (dstPixel[0] + (result[0] - dstPixel[0]) * alpha) & 0xFF) << 16 |
-                                   ((int) (dstPixel[1] + (result[1] - dstPixel[1]) * alpha) & 0xFF) <<  8 |
+                if (alpha != 0) {
+                    src.getDataElements(0, y, width, 1, srcPixels);
+                    for (int x = 0; x < width; x++) {
+                        // pixels are stored as INT_ARGB
+                        // our arrays are [R, G, B, A]
+                        int pixel = srcPixels[x];
+                        srcPixel[0] = (pixel >> 16) & 0xFF;
+                        srcPixel[1] = (pixel >>  8) & 0xFF;
+                        srcPixel[2] = (pixel      ) & 0xFF;
+                        srcPixel[3] = (pixel >> 24) & 0xFF;
+
+                        pixel = dstPixels[x];
+                        dstPixel[0] = (pixel >> 16) & 0xFF;
+                        dstPixel[1] = (pixel >>  8) & 0xFF;
+                        dstPixel[2] = (pixel      ) & 0xFF;
+                        dstPixel[3] = (pixel >> 24) & 0xFF;
+
+                        result = blender.blend(srcPixel, dstPixel, result);
+
+                        // mixes the result with the opacity
+                        if (alpha == 1) {
+                            dstPixels[x] = (result[3] & 0xFF) << 24 |
+                                           (result[0] & 0xFF) << 16 |
+                                           (result[1] & 0xFF) <<  8 |
+                                           result[2] & 0xFF;
+                        } else {
+                            dstPixels[x] =
+                                    ((int) (dstPixel[3] + (result[3] - dstPixel[3]) * alpha) & 0xFF) << 24 |
+                                    ((int) (dstPixel[0] + (result[0] - dstPixel[0]) * alpha) & 0xFF) << 16 |
+                                    ((int) (dstPixel[1] + (result[1] - dstPixel[1]) * alpha) & 0xFF) <<  8 |
                                     (int) (dstPixel[2] + (result[2] - dstPixel[2]) * alpha) & 0xFF;
-                }
+                        }
+
+                    }
+            }
                 dstOut.setDataElements(0, y, width, 1, dstPixels);
             }
         }
     }
 
     private static abstract class Blender {
-        public abstract int[] blend(int[] src, int[] dst);
+        public abstract int[] blend(int[] src, int[] dst, int[] result);
 
         private static void RGBtoHSL(int r, int g, int b, float[] hsl) {
             float var_R = (r / 255f);
@@ -346,56 +358,50 @@ public final class BlendComposite implements Composite {
                 case NORMAL:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return src;
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            System.arraycopy(src, 0, result, 0, 4);
+                            return result;
                         }
                     };
                 case ADD:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                Math.min(255, src[0] + dst[0]),
-                                Math.min(255, src[1] + dst[1]),
-                                Math.min(255, src[2] + dst[2]),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 4; i++) {
+                                result[i] = Math.min(255, src[i] + dst[i]);
+                            }
+                            return result;
                         }
                     };
                 case AVERAGE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                (src[0] + dst[0]) >> 1,
-                                (src[1] + dst[1]) >> 1,
-                                (src[2] + dst[2]) >> 1,
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = (src[i] + dst[i]) >> 1;
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case BLUE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                dst[0],
-                                src[1],
-                                dst[2],
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            System.arraycopy(dst, 0, result, 0, 3);
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case COLOR:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             float[] srcHSL = new float[3];
                             RGBtoHSL(src[0], src[1], src[2], srcHSL);
                             float[] dstHSL = new float[3];
                             RGBtoHSL(dst[0], dst[1], dst[2], dstHSL);
 
-                            int[] result = new int[4];
                             HSLtoRGB(srcHSL[0], srcHSL[1], dstHSL[2], result);
                             result[3] = Math.min(255, src[3] + dst[3]);
 
@@ -405,97 +411,88 @@ public final class BlendComposite implements Composite {
                 case COLOR_BURN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                src[0] == 0 ? 0 :
-                                    Math.max(0, 255 - (((255 - dst[0]) << 8) / src[0])),
-                                src[1] == 0 ? 0 :
-                                    Math.max(0, 255 - (((255 - dst[1]) << 8) / src[1])),
-                                src[2] == 0 ? 0 :
-                                    Math.max(0, 255 - (((255 - dst[2]) << 8) / src[2])),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = src[i] == 0 ? 0 :
+                                    Math.max(0, 255 - (((255 - dst[i]) << 8) / src[i]));
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case COLOR_DODGE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                src[0] == 255 ? 255 :
-                                    Math.min((dst[0] << 8) / (255 - src[0]), 255),
-                                src[1] == 255 ? 255 :
-                                    Math.min((dst[1] << 8) / (255 - src[1]), 255),
-                                src[2] == 255 ? 255 :
-                                    Math.min((dst[2] << 8) / (255 - src[2]), 255),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = src[i] == 255 ? 255 :
+                                    Math.min((dst[i] << 8) / (255 - src[i]), 255);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case DARKEN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                Math.min(src[0], dst[0]),
-                                Math.min(src[1], dst[1]),
-                                Math.min(src[2], dst[2]),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = Math.min(src[i], dst[i]);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case DIFFERENCE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                Math.abs(dst[0] - src[0]),
-                                Math.abs(dst[1] - src[1]),
-                                Math.abs(dst[2] - src[2]),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = dst[i] + src[i] - (dst[i] * src[i] >> 7);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case EXCLUSION:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                dst[0] + src[0] - (dst[0] * src[0] >> 7),
-                                dst[1] + src[1] - (dst[1] * src[1] >> 7),
-                                dst[2] + src[2] - (dst[2] * src[2] >> 7),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = dst[i] + src[i] - (dst[i] * src[i] >> 7);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case FREEZE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                src[0] == 0 ? 0 : Math.max(0, 255 - (255 - dst[0]) * (255 - dst[0]) / src[0]),
-                                src[1] == 0 ? 0 : Math.max(0, 255 - (255 - dst[1]) * (255 - dst[1]) / src[1]),
-                                src[2] == 0 ? 0 : Math.max(0, 255 - (255 - dst[2]) * (255 - dst[2]) / src[2]),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = src[i] == 0 ? 0 :
+                                    Math.max(0, 255 - (255 - dst[i]) * (255 - dst[i]) / src[i]);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case GLOW:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                dst[0] == 255 ? 255 : Math.min(255, src[0] * src[0] / (255 - dst[0])),
-                                dst[1] == 255 ? 255 : Math.min(255, src[1] * src[1] / (255 - dst[1])),
-                                dst[2] == 255 ? 255 : Math.min(255, src[2] * src[2] / (255 - dst[2])),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = dst[i] == 255 ? 255 :
+                                    Math.min(255, src[i] * src[i] / (255 - dst[i]));
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case GREEN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0],
                                 dst[1],
@@ -507,7 +504,7 @@ public final class BlendComposite implements Composite {
                 case HARD_LIGHT:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 src[0] < 128 ? dst[0] * src[0] >> 7 :
                                     255 - ((255 - src[0]) * (255 - dst[0]) >> 7),
@@ -522,7 +519,7 @@ public final class BlendComposite implements Composite {
                 case HEAT:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0] == 0 ? 0 : Math.max(0, 255 - (255 - src[0]) * (255 - src[0]) / dst[0]),
                                 dst[1] == 0 ? 0 : Math.max(0, 255 - (255 - src[1]) * (255 - src[1]) / dst[1]),
@@ -534,13 +531,12 @@ public final class BlendComposite implements Composite {
                 case HUE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             float[] srcHSL = new float[3];
                             RGBtoHSL(src[0], src[1], src[2], srcHSL);
                             float[] dstHSL = new float[3];
                             RGBtoHSL(dst[0], dst[1], dst[2], dstHSL);
 
-                            int[] result = new int[4];
                             HSLtoRGB(srcHSL[0], dstHSL[1], dstHSL[2], result);
                             result[3] = Math.min(255, src[3] + dst[3]);
 
@@ -550,7 +546,7 @@ public final class BlendComposite implements Composite {
                 case INVERSE_COLOR_BURN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0] == 0 ? 0 :
                                     Math.max(0, 255 - (((255 - src[0]) << 8) / dst[0])),
@@ -565,7 +561,7 @@ public final class BlendComposite implements Composite {
                 case INVERSE_COLOR_DODGE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0] == 255 ? 255 :
                                     Math.min((src[0] << 8) / (255 - dst[0]), 255),
@@ -580,25 +576,23 @@ public final class BlendComposite implements Composite {
                 case LIGHTEN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                Math.max(src[0], dst[0]),
-                                Math.max(src[1], dst[1]),
-                                Math.max(src[2], dst[2]),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = Math.max(src[i], dst[i]);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case LUMINOSITY:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             float[] srcHSL = new float[3];
                             RGBtoHSL(src[0], src[1], src[2], srcHSL);
                             float[] dstHSL = new float[3];
                             RGBtoHSL(dst[0], dst[1], dst[2], dstHSL);
 
-                            int[] result = new int[4];
                             HSLtoRGB(dstHSL[0], dstHSL[1], srcHSL[2], result);
                             result[3] = Math.min(255, src[3] + dst[3]);
 
@@ -608,19 +602,18 @@ public final class BlendComposite implements Composite {
                 case MULTIPLY:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                (src[0] * dst[0]) >> 8,
-                                (src[1] * dst[1]) >> 8,
-                                (src[2] * dst[2]) >> 8,
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = (src[i] * dst[i]) >> 8;
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case NEGATION:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 255 - Math.abs(255 - dst[0] - src[0]),
                                 255 - Math.abs(255 - dst[1] - src[1]),
@@ -632,22 +625,19 @@ public final class BlendComposite implements Composite {
                 case OVERLAY:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
-                            return new int[] {
-                                dst[0] < 128 ? dst[0] * src[0] >> 7 :
-                                    255 - ((255 - dst[0]) * (255 - src[0]) >> 7),
-                                dst[1] < 128 ? dst[1] * src[1] >> 7 :
-                                    255 - ((255 - dst[1]) * (255 - src[1]) >> 7),
-                                dst[2] < 128 ? dst[2] * src[2] >> 7 :
-                                    255 - ((255 - dst[2]) * (255 - src[2]) >> 7),
-                                Math.min(255, src[3] + dst[3])
-                            };
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            for (int i = 0; i < 3; i++) {
+                                result[i] = dst[i] < 128 ? dst[i] * src[i] >> 7 :
+                                    255 - ((255 - dst[i]) * (255 - src[i]) >> 7);
+                            }
+                            result[3] = Math.min(255, src[3] + dst[3]);
+                            return result;
                         }
                     };
                 case RED:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 src[0],
                                 dst[1],
@@ -659,7 +649,7 @@ public final class BlendComposite implements Composite {
                 case REFLECT:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 src[0] == 255 ? 255 : Math.min(255, dst[0] * dst[0] / (255 - src[0])),
                                 src[1] == 255 ? 255 : Math.min(255, dst[1] * dst[1] / (255 - src[1])),
@@ -671,13 +661,12 @@ public final class BlendComposite implements Composite {
                 case SATURATION:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             float[] srcHSL = new float[3];
                             RGBtoHSL(src[0], src[1], src[2], srcHSL);
                             float[] dstHSL = new float[3];
                             RGBtoHSL(dst[0], dst[1], dst[2], dstHSL);
 
-                            int[] result = new int[4];
                             HSLtoRGB(dstHSL[0], srcHSL[1], dstHSL[2], result);
                             result[3] = Math.min(255, src[3] + dst[3]);
 
@@ -687,7 +676,7 @@ public final class BlendComposite implements Composite {
                 case SCREEN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 255 - ((255 - src[0]) * (255 - dst[0]) >> 8),
                                 255 - ((255 - src[1]) * (255 - dst[1]) >> 8),
@@ -699,7 +688,7 @@ public final class BlendComposite implements Composite {
                 case SOFT_BURN:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0] + src[0] < 256 ?
 	                                (dst[0] == 255 ? 255 :
@@ -720,7 +709,7 @@ public final class BlendComposite implements Composite {
                 case SOFT_DODGE:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 dst[0] + src[0] < 256 ?
                                     (src[0] == 255 ? 255 :
@@ -743,7 +732,7 @@ public final class BlendComposite implements Composite {
                 case STAMP:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 Math.max(0, Math.min(255, dst[0] + 2 * src[0] - 256)),
                                 Math.max(0, Math.min(255, dst[1] + 2 * src[1] - 256)),
@@ -755,7 +744,7 @@ public final class BlendComposite implements Composite {
                 case SUBTRACT:
                     return new Blender() {
                         @Override
-                        public int[] blend(int[] src, int[] dst) {
+                        public int[] blend(int[] src, int[] dst, int[] result) {
                             return new int[] {
                                 Math.max(0, src[0] + dst[0] - 256),
                                 Math.max(0, src[1] + dst[1] - 256),