1 /* 2 * Copyright 2018 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 // This master effect implements clamping on the layout coordinate and requires specifying the 9 // border colors that are used when outside the clamped boundary. Gradients with the 10 // SkShader::kClamp_TileMode should use the colors at their first and last stop (after adding dummy 11 // stops for t=0,t=1) as the border color. This will automatically replicate the edge color, even if 12 // when there is a hard stop. 13 // 14 // The SkShader::kDecal_TileMode can be produced by specifying transparent black as the border 15 // colors, regardless of the gradient's stop colors. 16 17 in fragmentProcessor colorizer; 18 in fragmentProcessor gradLayout; 19 20 layout(ctype=SkPMColor4f, tracked) in uniform half4 leftBorderColor; // t < 0.0 21 layout(ctype=SkPMColor4f, tracked) in uniform half4 rightBorderColor; // t > 1.0 22 23 layout(key) in bool makePremul; 24 // Trust the creator that this matches the color spec of the gradient 25 in bool colorsAreOpaque; 26 27 void main() { 28 half4 t = process(gradLayout); 29 // If t.x is below 0, use the left border color without invoking the child processor. If any t.x 30 // is above 1, use the right border color. Otherwise, t is in the [0, 1] range assumed by the 31 // colorizer FP, so delegate to the child processor. 32 if (!gradLayout.preservesOpaqueInput && t.y < 0) { 33 // layout has rejected this fragment (rely on sksl to remove this branch if the layout FP 34 // preserves opacity is false) 35 sk_OutColor = half4(0); 36 } else if (t.x < 0) { 37 sk_OutColor = leftBorderColor; 38 } else if (t.x > 1.0) { 39 sk_OutColor = rightBorderColor; 40 } else { 41 sk_OutColor = process(colorizer, t); 42 } 43 44 @if(makePremul) { 45 sk_OutColor.xyz *= sk_OutColor.w; 46 } 47 } 48 49 ////////////////////////////////////////////////////////////////////////////// 50 51 // If the layout does not preserve opacity, remove the opaque optimization, 52 // but otherwise respect the provided color opacity state (which should take 53 // into account the opacity of the border colors). 54 @optimizationFlags { 55 kCompatibleWithCoverageAsAlpha_OptimizationFlag | 56 (colorsAreOpaque && gradLayout->preservesOpaqueInput() ? kPreservesOpaqueInput_OptimizationFlag 57 : kNone_OptimizationFlags) 58 } 59
