/* * Copyright 2018 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ // This master effect implements clamping on the layout coordinate and requires specifying the // border colors that are used when outside the clamped boundary. Gradients with the // SkShader::kClamp_TileMode should use the colors at their first and last stop (after adding dummy // stops for t=0,t=1) as the border color. This will automatically replicate the edge color, even if // when there is a hard stop. // // The SkShader::kDecal_TileMode can be produced by specifying transparent black as the border // colors, regardless of the gradient's stop colors. in fragmentProcessor colorizer; in fragmentProcessor gradLayout; layout(ctype=SkPMColor4f, tracked) in uniform half4 leftBorderColor; // t < 0.0 layout(ctype=SkPMColor4f, tracked) in uniform half4 rightBorderColor; // t > 1.0 layout(key) in bool makePremul; // Trust the creator that this matches the color spec of the gradient in bool colorsAreOpaque; void main() { half4 t = process(gradLayout); // If t.x is below 0, use the left border color without invoking the child processor. If any t.x // is above 1, use the right border color. Otherwise, t is in the [0, 1] range assumed by the // colorizer FP, so delegate to the child processor. if (!gradLayout.preservesOpaqueInput && t.y < 0) { // layout has rejected this fragment (rely on sksl to remove this branch if the layout FP // preserves opacity is false) sk_OutColor = half4(0); } else if (t.x < 0) { sk_OutColor = leftBorderColor; } else if (t.x > 1.0) { sk_OutColor = rightBorderColor; } else { sk_OutColor = process(colorizer, t); } @if(makePremul) { sk_OutColor.xyz *= sk_OutColor.w; } } ////////////////////////////////////////////////////////////////////////////// // If the layout does not preserve opacity, remove the opaque optimization, // but otherwise respect the provided color opacity state (which should take // into account the opacity of the border colors). @optimizationFlags { kCompatibleWithCoverageAsAlpha_OptimizationFlag | (colorsAreOpaque && gradLayout->preservesOpaqueInput() ? kPreservesOpaqueInput_OptimizationFlag : kNone_OptimizationFlags) }