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gerrit-public.fairphone.software / platform / external / skia / 520dadc72f90c52b29ddfc3d39f92176862eb3e0 / . / src / pdf / SkPDFShader.cpp
blob: fe6e47c1db0f049307969097919a9426c72788c8 [file] [log] [blame]
/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkPDFShader.h"
#include "SkData.h"
#include "SkOncePtr.h"
#include "SkPDFCanon.h"
#include "SkPDFDevice.h"
#include "SkPDFFormXObject.h"
#include "SkPDFGraphicState.h"
#include "SkPDFResourceDict.h"
#include "SkPDFUtils.h"
#include "SkScalar.h"
#include "SkStream.h"
#include "SkTemplates.h"
#include "SkTypes.h"
static bool inverse_transform_bbox(const SkMatrix& matrix, SkRect* bbox) {
SkMatrix inverse;
if (!matrix.invert(&inverse)) {
return false;
}
inverse.mapRect(bbox);
return true;
}
static void unitToPointsMatrix(const SkPoint pts[2], SkMatrix* matrix) {
SkVector vec = pts[1] - pts[0];
SkScalar mag = vec.length();
SkScalar inv = mag ? SkScalarInvert(mag) : 0;
vec.scale(inv);
matrix->setSinCos(vec.fY, vec.fX);
matrix->preScale(mag, mag);
matrix->postTranslate(pts[0].fX, pts[0].fY);
}
/* Assumes t + startOffset is on the stack and does a linear interpolation on t
between startOffset and endOffset from prevColor to curColor (for each color
component), leaving the result in component order on the stack. It assumes
there are always 3 components per color.
@param range endOffset - startOffset
@param curColor[components] The current color components.
@param prevColor[components] The previous color components.
@param result The result ps function.
*/
static void interpolateColorCode(SkScalar range, SkScalar* curColor,
SkScalar* prevColor, SkString* result) {
SkASSERT(range != SkIntToScalar(0));
static const int kColorComponents = 3;
// Figure out how to scale each color component.
SkScalar multiplier[kColorComponents];
for (int i = 0; i < kColorComponents; i++) {
multiplier[i] = (curColor[i] - prevColor[i]) / range;
}
// Calculate when we no longer need to keep a copy of the input parameter t.
// If the last component to use t is i, then dupInput[0..i - 1] = true
// and dupInput[i .. components] = false.
bool dupInput[kColorComponents];
dupInput[kColorComponents - 1] = false;
for (int i = kColorComponents - 2; i >= 0; i--) {
dupInput[i] = dupInput[i + 1] || multiplier[i + 1] != 0;
}
if (!dupInput[0] && multiplier[0] == 0) {
result->append("pop ");
}
for (int i = 0; i < kColorComponents; i++) {
// If the next components needs t and this component will consume a
// copy, make another copy.
if (dupInput[i] && multiplier[i] != 0) {
result->append("dup ");
}
if (multiplier[i] == 0) {
result->appendScalar(prevColor[i]);
result->append(" ");
} else {
if (multiplier[i] != 1) {
result->appendScalar(multiplier[i]);
result->append(" mul ");
}
if (prevColor[i] != 0) {
result->appendScalar(prevColor[i]);
result->append(" add ");
}
}
if (dupInput[i]) {
result->append("exch\n");
}
}
}
/* Generate Type 4 function code to map t=[0,1) to the passed gradient,
clamping at the edges of the range. The generated code will be of the form:
if (t < 0) {
return colorData[0][r,g,b];
} else {
if (t < info.fColorOffsets[1]) {
return linearinterpolation(colorData[0][r,g,b],
colorData[1][r,g,b]);
} else {
if (t < info.fColorOffsets[2]) {
return linearinterpolation(colorData[1][r,g,b],
colorData[2][r,g,b]);
} else {
... } else {
return colorData[info.fColorCount - 1][r,g,b];
}
...
}
}
*/
static void gradientFunctionCode(const SkShader::GradientInfo& info,
SkString* result) {
/* We want to linearly interpolate from the previous color to the next.
Scale the colors from 0..255 to 0..1 and determine the multipliers
for interpolation.
C{r,g,b}(t, section) = t - offset_(section-1) + t * Multiplier{r,g,b}.
*/
static const int kColorComponents = 3;
typedef SkScalar ColorTuple[kColorComponents];
SkAutoSTMalloc<4, ColorTuple> colorDataAlloc(info.fColorCount);
ColorTuple *colorData = colorDataAlloc.get();
const SkScalar scale = SkScalarInvert(SkIntToScalar(255));
for (int i = 0; i < info.fColorCount; i++) {
colorData[i][0] = SkScalarMul(SkColorGetR(info.fColors[i]), scale);
colorData[i][1] = SkScalarMul(SkColorGetG(info.fColors[i]), scale);
colorData[i][2] = SkScalarMul(SkColorGetB(info.fColors[i]), scale);
}
// Clamp the initial color.
result->append("dup 0 le {pop ");
result->appendScalar(colorData[0][0]);
result->append(" ");
result->appendScalar(colorData[0][1]);
result->append(" ");
result->appendScalar(colorData[0][2]);
result->append(" }\n");
// The gradient colors.
int gradients = 0;
for (int i = 1 ; i < info.fColorCount; i++) {
if (info.fColorOffsets[i] == info.fColorOffsets[i - 1]) {
continue;
}
gradients++;
result->append("{dup ");
result->appendScalar(info.fColorOffsets[i]);
result->append(" le {");
if (info.fColorOffsets[i - 1] != 0) {
result->appendScalar(info.fColorOffsets[i - 1]);
result->append(" sub\n");
}
interpolateColorCode(info.fColorOffsets[i] - info.fColorOffsets[i - 1],
colorData[i], colorData[i - 1], result);
result->append("}\n");
}
// Clamp the final color.
result->append("{pop ");
result->appendScalar(colorData[info.fColorCount - 1][0]);
result->append(" ");
result->appendScalar(colorData[info.fColorCount - 1][1]);
result->append(" ");
result->appendScalar(colorData[info.fColorCount - 1][2]);
for (int i = 0 ; i < gradients + 1; i++) {
result->append("} ifelse\n");
}
}
/* Map a value of t on the stack into [0, 1) for Repeat or Mirror tile mode. */
static void tileModeCode(SkShader::TileMode mode, SkString* result) {
if (mode == SkShader::kRepeat_TileMode) {
result->append("dup truncate sub\n"); // Get the fractional part.
result->append("dup 0 le {1 add} if\n"); // Map (-1,0) => (0,1)
return;
}
if (mode == SkShader::kMirror_TileMode) {
// Map t mod 2 into [0, 1, 1, 0].
// Code Stack
result->append("abs " // Map negative to positive.
"dup " // t.s t.s
"truncate " // t.s t
"dup " // t.s t t
"cvi " // t.s t T
"2 mod " // t.s t (i mod 2)
"1 eq " // t.s t true|false
"3 1 roll " // true|false t.s t
"sub " // true|false 0.s
"exch " // 0.s true|false
"{1 exch sub} if\n"); // 1 - 0.s|0.s
}
}
/**
* Returns PS function code that applies inverse perspective
* to a x, y point.
* The function assumes that the stack has at least two elements,
* and that the top 2 elements are numeric values.
* After executing this code on a PS stack, the last 2 elements are updated
* while the rest of the stack is preserved intact.
* inversePerspectiveMatrix is the inverse perspective matrix.
*/
static SkString apply_perspective_to_coordinates(
const SkMatrix& inversePerspectiveMatrix) {
SkString code;
if (!inversePerspectiveMatrix.hasPerspective()) {
return code;
}
// Perspective matrix should be:
// 1 0 0
// 0 1 0
// p0 p1 p2
const SkScalar p0 = inversePerspectiveMatrix[SkMatrix::kMPersp0];
const SkScalar p1 = inversePerspectiveMatrix[SkMatrix::kMPersp1];
const SkScalar p2 = inversePerspectiveMatrix[SkMatrix::kMPersp2];
// y = y / (p2 + p0 x + p1 y)
// x = x / (p2 + p0 x + p1 y)
// Input on stack: x y
code.append(" dup "); // x y y
code.appendScalar(p1); // x y y p1
code.append(" mul " // x y y*p1
" 2 index "); // x y y*p1 x
code.appendScalar(p0); // x y y p1 x p0
code.append(" mul "); // x y y*p1 x*p0
code.appendScalar(p2); // x y y p1 x*p0 p2
code.append(" add " // x y y*p1 x*p0+p2
"add " // x y y*p1+x*p0+p2
"3 1 roll " // y*p1+x*p0+p2 x y
"2 index " // z x y y*p1+x*p0+p2
"div " // y*p1+x*p0+p2 x y/(y*p1+x*p0+p2)
"3 1 roll " // y/(y*p1+x*p0+p2) y*p1+x*p0+p2 x
"exch " // y/(y*p1+x*p0+p2) x y*p1+x*p0+p2
"div " // y/(y*p1+x*p0+p2) x/(y*p1+x*p0+p2)
"exch\n"); // x/(y*p1+x*p0+p2) y/(y*p1+x*p0+p2)
return code;
}
static SkString linearCode(const SkShader::GradientInfo& info,
const SkMatrix& perspectiveRemover) {
SkString function("{");
function.append(apply_perspective_to_coordinates(perspectiveRemover));
function.append("pop\n"); // Just ditch the y value.
tileModeCode(info.fTileMode, &function);
gradientFunctionCode(info, &function);
function.append("}");
return function;
}
static SkString radialCode(const SkShader::GradientInfo& info,
const SkMatrix& perspectiveRemover) {
SkString function("{");
function.append(apply_perspective_to_coordinates(perspectiveRemover));
// Find the distance from the origin.
function.append("dup " // x y y
"mul " // x y^2
"exch " // y^2 x
"dup " // y^2 x x
"mul " // y^2 x^2
"add " // y^2+x^2
"sqrt\n"); // sqrt(y^2+x^2)
tileModeCode(info.fTileMode, &function);
gradientFunctionCode(info, &function);
function.append("}");
return function;
}
/* Conical gradient shader, based on the Canvas spec for radial gradients
See: http://www.w3.org/TR/2dcontext/#dom-context-2d-createradialgradient
*/
static SkString twoPointConicalCode(const SkShader::GradientInfo& info,
const SkMatrix& perspectiveRemover) {
SkScalar dx = info.fPoint[1].fX - info.fPoint[0].fX;
SkScalar dy = info.fPoint[1].fY - info.fPoint[0].fY;
SkScalar r0 = info.fRadius[0];
SkScalar dr = info.fRadius[1] - info.fRadius[0];
SkScalar a = SkScalarMul(dx, dx) + SkScalarMul(dy, dy) -
SkScalarMul(dr, dr);
// First compute t, if the pixel falls outside the cone, then we'll end
// with 'false' on the stack, otherwise we'll push 'true' with t below it
// We start with a stack of (x y), copy it and then consume one copy in
// order to calculate b and the other to calculate c.
SkString function("{");
function.append(apply_perspective_to_coordinates(perspectiveRemover));
function.append("2 copy ");
// Calculate b and b^2; b = -2 * (y * dy + x * dx + r0 * dr).
function.appendScalar(dy);
function.append(" mul exch ");
function.appendScalar(dx);
function.append(" mul add ");
function.appendScalar(SkScalarMul(r0, dr));
function.append(" add -2 mul dup dup mul\n");
// c = x^2 + y^2 + radius0^2
function.append("4 2 roll dup mul exch dup mul add ");
function.appendScalar(SkScalarMul(r0, r0));
function.append(" sub dup 4 1 roll\n");
// Contents of the stack at this point: c, b, b^2, c
// if a = 0, then we collapse to a simpler linear case
if (a == 0) {
// t = -c/b
function.append("pop pop div neg dup ");
// compute radius(t)
function.appendScalar(dr);
function.append(" mul ");
function.appendScalar(r0);
function.append(" add\n");
// if r(t) < 0, then it's outside the cone
function.append("0 lt {pop false} {true} ifelse\n");
} else {
// quadratic case: the Canvas spec wants the largest
// root t for which radius(t) > 0
// compute the discriminant (b^2 - 4ac)
function.appendScalar(SkScalarMul(SkIntToScalar(4), a));
function.append(" mul sub dup\n");
// if d >= 0, proceed
function.append("0 ge {\n");
// an intermediate value we'll use to compute the roots:
// q = -0.5 * (b +/- sqrt(d))
function.append("sqrt exch dup 0 lt {exch -1 mul} if");
function.append(" add -0.5 mul dup\n");
// first root = q / a
function.appendScalar(a);
function.append(" div\n");
// second root = c / q
function.append("3 1 roll div\n");
// put the larger root on top of the stack
function.append("2 copy gt {exch} if\n");
// compute radius(t) for larger root
function.append("dup ");
function.appendScalar(dr);
function.append(" mul ");
function.appendScalar(r0);
function.append(" add\n");
// if r(t) > 0, we have our t, pop off the smaller root and we're done
function.append(" 0 gt {exch pop true}\n");
// otherwise, throw out the larger one and try the smaller root
function.append("{pop dup\n");
function.appendScalar(dr);
function.append(" mul ");
function.appendScalar(r0);
function.append(" add\n");
// if r(t) < 0, push false, otherwise the smaller root is our t
function.append("0 le {pop false} {true} ifelse\n");
function.append("} ifelse\n");
// d < 0, clear the stack and push false
function.append("} {pop pop pop false} ifelse\n");
}
// if the pixel is in the cone, proceed to compute a color
function.append("{");
tileModeCode(info.fTileMode, &function);
gradientFunctionCode(info, &function);
// otherwise, just write black
function.append("} {0 0 0} ifelse }");
return function;
}
static SkString sweepCode(const SkShader::GradientInfo& info,
const SkMatrix& perspectiveRemover) {
SkString function("{exch atan 360 div\n");
tileModeCode(info.fTileMode, &function);
gradientFunctionCode(info, &function);
function.append("}");
return function;
}
static void drawBitmapMatrix(SkCanvas* canvas, const SkBitmap& bm, const SkMatrix& matrix) {
SkAutoCanvasRestore acr(canvas, true);
canvas->concat(matrix);
canvas->drawBitmap(bm, 0, 0);
}
class SkPDFShader::State {
public:
SkShader::GradientType fType;
SkShader::GradientInfo fInfo;
SkAutoFree fColorData; // This provides storage for arrays in fInfo.
SkMatrix fCanvasTransform;
SkMatrix fShaderTransform;
SkIRect fBBox;
SkBitmap fImage;
uint32_t fPixelGeneration;
SkShader::TileMode fImageTileModes[2];
State(const SkShader& shader, const SkMatrix& canvasTransform,
const SkIRect& bbox, SkScalar rasterScale);
bool operator==(const State& b) const;
SkPDFShader::State* CreateAlphaToLuminosityState() const;
SkPDFShader::State* CreateOpaqueState() const;
bool GradientHasAlpha() const;
private:
State(const State& other);
State operator=(const State& rhs);
void AllocateGradientInfoStorage();
};
////////////////////////////////////////////////////////////////////////////////
SkPDFFunctionShader::SkPDFFunctionShader(SkPDFShader::State* state)
: SkPDFDict("Pattern"), fShaderState(state) {}
SkPDFFunctionShader::~SkPDFFunctionShader() {}
bool SkPDFFunctionShader::equals(const SkPDFShader::State& state) const {
return state == *fShaderState;
}
////////////////////////////////////////////////////////////////////////////////
SkPDFAlphaFunctionShader::SkPDFAlphaFunctionShader(SkPDFShader::State* state)
: fShaderState(state) {}
bool SkPDFAlphaFunctionShader::equals(const SkPDFShader::State& state) const {
return state == *fShaderState;
}
SkPDFAlphaFunctionShader::~SkPDFAlphaFunctionShader() {}
////////////////////////////////////////////////////////////////////////////////
SkPDFImageShader::SkPDFImageShader(SkPDFShader::State* state)
: fShaderState(state) {}
bool SkPDFImageShader::equals(const SkPDFShader::State& state) const {
return state == *fShaderState;
}
SkPDFImageShader::~SkPDFImageShader() {}
////////////////////////////////////////////////////////////////////////////////
static SkPDFObject* get_pdf_shader_by_state(
SkPDFCanon* canon,
SkScalar dpi,
SkAutoTDelete<SkPDFShader::State>* autoState) {
const SkPDFShader::State& state = **autoState;
if (state.fType == SkShader::kNone_GradientType && state.fImage.isNull()) {
// TODO(vandebo) This drops SKComposeShader on the floor. We could
// handle compose shader by pulling things up to a layer, drawing with
// the first shader, applying the xfer mode and drawing again with the
// second shader, then applying the layer to the original drawing.
return nullptr;
} else if (state.fType == SkShader::kNone_GradientType) {
SkPDFObject* shader = canon->findImageShader(state);
return shader ? SkRef(shader)
: SkPDFImageShader::Create(canon, dpi, autoState);
} else if (state.GradientHasAlpha()) {
SkPDFObject* shader = canon->findAlphaShader(state);
return shader ? SkRef(shader)
: SkPDFAlphaFunctionShader::Create(canon, dpi, autoState);
} else {
SkPDFObject* shader = canon->findFunctionShader(state);
return shader ? SkRef(shader)
: SkPDFFunctionShader::Create(canon, autoState);
}
}
// static
SkPDFObject* SkPDFShader::GetPDFShader(SkPDFCanon* canon,
SkScalar dpi,
const SkShader& shader,
const SkMatrix& matrix,
const SkIRect& surfaceBBox,
SkScalar rasterScale) {
SkAutoTDelete<SkPDFShader::State> state(new State(shader, matrix, surfaceBBox, rasterScale));
return get_pdf_shader_by_state(canon, dpi, &state);
}
static SkPDFDict* get_gradient_resource_dict(
SkPDFObject* functionShader,
SkPDFObject* gState) {
SkTDArray<SkPDFObject*> patterns;
if (functionShader) {
patterns.push(functionShader);
}
SkTDArray<SkPDFObject*> graphicStates;
if (gState) {
graphicStates.push(gState);
}
return SkPDFResourceDict::Create(&graphicStates, &patterns, nullptr, nullptr);
}
static void populate_tiling_pattern_dict(SkPDFDict* pattern,
SkRect& bbox,
SkPDFDict* resources,
const SkMatrix& matrix) {
const int kTiling_PatternType = 1;
const int kColoredTilingPattern_PaintType = 1;
const int kConstantSpacing_TilingType = 1;
pattern->insertName("Type", "Pattern");
pattern->insertInt("PatternType", kTiling_PatternType);
pattern->insertInt("PaintType", kColoredTilingPattern_PaintType);
pattern->insertInt("TilingType", kConstantSpacing_TilingType);
pattern->insertObject("BBox", SkPDFUtils::RectToArray(bbox));
pattern->insertScalar("XStep", bbox.width());
pattern->insertScalar("YStep", bbox.height());
pattern->insertObject("Resources", SkRef(resources));
if (!matrix.isIdentity()) {
pattern->insertObject("Matrix", SkPDFUtils::MatrixToArray(matrix));
}
}
/**
* Creates a content stream which fills the pattern P0 across bounds.
* @param gsIndex A graphics state resource index to apply, or <0 if no
* graphics state to apply.
*/
static SkStream* create_pattern_fill_content(int gsIndex, SkRect& bounds) {
SkDynamicMemoryWStream content;
if (gsIndex >= 0) {
SkPDFUtils::ApplyGraphicState(gsIndex, &content);
}
SkPDFUtils::ApplyPattern(0, &content);
SkPDFUtils::AppendRectangle(bounds, &content);
SkPDFUtils::PaintPath(SkPaint::kFill_Style, SkPath::kEvenOdd_FillType,
&content);
return content.detachAsStream();
}
/**
* Creates a ExtGState with the SMask set to the luminosityShader in
* luminosity mode. The shader pattern extends to the bbox.
*/
static SkPDFObject* create_smask_graphic_state(
SkPDFCanon* canon, SkScalar dpi, const SkPDFShader::State& state) {
SkRect bbox;
bbox.set(state.fBBox);
SkAutoTDelete<SkPDFShader::State> alphaToLuminosityState(
state.CreateAlphaToLuminosityState());
SkAutoTUnref<SkPDFObject> luminosityShader(
get_pdf_shader_by_state(canon, dpi, &alphaToLuminosityState));
SkAutoTDelete<SkStream> alphaStream(create_pattern_fill_content(-1, bbox));
SkAutoTUnref<SkPDFDict>
resources(get_gradient_resource_dict(luminosityShader, nullptr));
SkAutoTUnref<SkPDFFormXObject> alphaMask(
new SkPDFFormXObject(alphaStream.get(), bbox, resources.get()));
return SkPDFGraphicState::GetSMaskGraphicState(
alphaMask.get(), false,
SkPDFGraphicState::kLuminosity_SMaskMode);
}
SkPDFAlphaFunctionShader* SkPDFAlphaFunctionShader::Create(
SkPDFCanon* canon,
SkScalar dpi,
SkAutoTDelete<SkPDFShader::State>* autoState) {
const SkPDFShader::State& state = **autoState;
SkRect bbox;
bbox.set(state.fBBox);
SkAutoTDelete<SkPDFShader::State> opaqueState(state.CreateOpaqueState());
SkAutoTUnref<SkPDFObject> colorShader(
get_pdf_shader_by_state(canon, dpi, &opaqueState));
if (!colorShader) {
return nullptr;
}
// Create resource dict with alpha graphics state as G0 and
// pattern shader as P0, then write content stream.
SkAutoTUnref<SkPDFObject> alphaGs(
create_smask_graphic_state(canon, dpi, state));
SkPDFAlphaFunctionShader* alphaFunctionShader =
new SkPDFAlphaFunctionShader(autoState->detach());
SkAutoTUnref<SkPDFDict> resourceDict(
get_gradient_resource_dict(colorShader.get(), alphaGs.get()));
SkAutoTDelete<SkStream> colorStream(
create_pattern_fill_content(0, bbox));
alphaFunctionShader->setData(colorStream.get());
populate_tiling_pattern_dict(alphaFunctionShader, bbox, resourceDict.get(),
SkMatrix::I());
canon->addAlphaShader(alphaFunctionShader);
return alphaFunctionShader;
}
// Finds affine and persp such that in = affine * persp.
// but it returns the inverse of perspective matrix.
static bool split_perspective(const SkMatrix in, SkMatrix* affine,
SkMatrix* perspectiveInverse) {
const SkScalar p2 = in[SkMatrix::kMPersp2];
if (SkScalarNearlyZero(p2)) {
return false;
}
const SkScalar zero = SkIntToScalar(0);
const SkScalar one = SkIntToScalar(1);
const SkScalar sx = in[SkMatrix::kMScaleX];
const SkScalar kx = in[SkMatrix::kMSkewX];
const SkScalar tx = in[SkMatrix::kMTransX];
const SkScalar ky = in[SkMatrix::kMSkewY];
const SkScalar sy = in[SkMatrix::kMScaleY];
const SkScalar ty = in[SkMatrix::kMTransY];
const SkScalar p0 = in[SkMatrix::kMPersp0];
const SkScalar p1 = in[SkMatrix::kMPersp1];
// Perspective matrix would be:
// 1 0 0
// 0 1 0
// p0 p1 p2
// But we need the inverse of persp.
perspectiveInverse->setAll(one, zero, zero,
zero, one, zero,
-p0/p2, -p1/p2, 1/p2);
affine->setAll(sx - p0 * tx / p2, kx - p1 * tx / p2, tx / p2,
ky - p0 * ty / p2, sy - p1 * ty / p2, ty / p2,
zero, zero, one);
return true;
}
static SkPDFObject* create_range_object() {
SkPDFArray* range = new SkPDFArray;
range->reserve(6);
range->appendInt(0);
range->appendInt(1);
range->appendInt(0);
range->appendInt(1);
range->appendInt(0);
range->appendInt(1);
return range;
}
SK_DECLARE_STATIC_ONCE_PTR(SkPDFObject, rangeObject);
static SkPDFStream* make_ps_function(const SkString& psCode,
SkPDFArray* domain) {
SkAutoDataUnref funcData(
SkData::NewWithCopy(psCode.c_str(), psCode.size()));
SkPDFStream* result = new SkPDFStream(funcData.get());
result->insertInt("FunctionType", 4);
result->insertObject("Domain", SkRef(domain));
result->insertObject("Range", SkRef(rangeObject.get(create_range_object)));
return result;
}
SkPDFFunctionShader* SkPDFFunctionShader::Create(
SkPDFCanon* canon, SkAutoTDelete<SkPDFShader::State>* autoState) {
const SkPDFShader::State& state = **autoState;
SkString (*codeFunction)(const SkShader::GradientInfo& info,
const SkMatrix& perspectiveRemover) = nullptr;
SkPoint transformPoints[2];
// Depending on the type of the gradient, we want to transform the
// coordinate space in different ways.
const SkShader::GradientInfo* info = &state.fInfo;
transformPoints[0] = info->fPoint[0];
transformPoints[1] = info->fPoint[1];
switch (state.fType) {
case SkShader::kLinear_GradientType:
codeFunction = &linearCode;
break;
case SkShader::kRadial_GradientType:
transformPoints[1] = transformPoints[0];
transformPoints[1].fX += info->fRadius[0];
codeFunction = &radialCode;
break;
case SkShader::kConical_GradientType: {
transformPoints[1] = transformPoints[0];
transformPoints[1].fX += SK_Scalar1;
codeFunction = &twoPointConicalCode;
break;
}
case SkShader::kSweep_GradientType:
transformPoints[1] = transformPoints[0];
transformPoints[1].fX += SK_Scalar1;
codeFunction = &sweepCode;
break;
case SkShader::kColor_GradientType:
case SkShader::kNone_GradientType:
default:
return nullptr;
}
// Move any scaling (assuming a unit gradient) or translation
// (and rotation for linear gradient), of the final gradient from
// info->fPoints to the matrix (updating bbox appropriately). Now
// the gradient can be drawn on on the unit segment.
SkMatrix mapperMatrix;
unitToPointsMatrix(transformPoints, &mapperMatrix);
SkMatrix finalMatrix = state.fCanvasTransform;
finalMatrix.preConcat(state.fShaderTransform);
finalMatrix.preConcat(mapperMatrix);
// Preserves as much as posible in the final matrix, and only removes
// the perspective. The inverse of the perspective is stored in
// perspectiveInverseOnly matrix and has 3 useful numbers
// (p0, p1, p2), while everything else is either 0 or 1.
// In this way the shader will handle it eficiently, with minimal code.
SkMatrix perspectiveInverseOnly = SkMatrix::I();
if (finalMatrix.hasPerspective()) {
if (!split_perspective(finalMatrix,
&finalMatrix, &perspectiveInverseOnly)) {
return nullptr;
}
}
SkRect bbox;
bbox.set(state.fBBox);
if (!inverse_transform_bbox(finalMatrix, &bbox)) {
return nullptr;
}
SkAutoTUnref<SkPDFArray> domain(new SkPDFArray);
domain->reserve(4);
domain->appendScalar(bbox.fLeft);
domain->appendScalar(bbox.fRight);
domain->appendScalar(bbox.fTop);
domain->appendScalar(bbox.fBottom);
SkString functionCode;
// The two point radial gradient further references
// state.fInfo
// in translating from x, y coordinates to the t parameter. So, we have
// to transform the points and radii according to the calculated matrix.
if (state.fType == SkShader::kConical_GradientType) {
SkShader::GradientInfo twoPointRadialInfo = *info;
SkMatrix inverseMapperMatrix;
if (!mapperMatrix.invert(&inverseMapperMatrix)) {
return nullptr;
}
inverseMapperMatrix.mapPoints(twoPointRadialInfo.fPoint, 2);
twoPointRadialInfo.fRadius[0] =
inverseMapperMatrix.mapRadius(info->fRadius[0]);
twoPointRadialInfo.fRadius[1] =
inverseMapperMatrix.mapRadius(info->fRadius[1]);
functionCode = codeFunction(twoPointRadialInfo, perspectiveInverseOnly);
} else {
functionCode = codeFunction(*info, perspectiveInverseOnly);
}
SkAutoTUnref<SkPDFDict> pdfShader(new SkPDFDict);
pdfShader->insertInt("ShadingType", 1);
pdfShader->insertName("ColorSpace", "DeviceRGB");
pdfShader->insertObject("Domain", SkRef(domain.get()));
SkAutoTUnref<SkPDFStream> function(
make_ps_function(functionCode, domain.get()));
pdfShader->insertObjRef("Function", function.detach());
SkPDFFunctionShader* pdfFunctionShader = new SkPDFFunctionShader(autoState->detach());
pdfFunctionShader->insertInt("PatternType", 2);
pdfFunctionShader->insertObject("Matrix",
SkPDFUtils::MatrixToArray(finalMatrix));
pdfFunctionShader->insertObject("Shading", pdfShader.detach());
canon->addFunctionShader(pdfFunctionShader);
return pdfFunctionShader;
}
SkPDFImageShader* SkPDFImageShader::Create(
SkPDFCanon* canon,
SkScalar dpi,
SkAutoTDelete<SkPDFShader::State>* autoState) {
const SkPDFShader::State& state = **autoState;
state.fImage.lockPixels();
// The image shader pattern cell will be drawn into a separate device
// in pattern cell space (no scaling on the bitmap, though there may be
// translations so that all content is in the device, coordinates > 0).
// Map clip bounds to shader space to ensure the device is large enough
// to handle fake clamping.
SkMatrix finalMatrix = state.fCanvasTransform;
finalMatrix.preConcat(state.fShaderTransform);
SkRect deviceBounds;
deviceBounds.set(state.fBBox);
if (!inverse_transform_bbox(finalMatrix, &deviceBounds)) {
return nullptr;
}
const SkBitmap* image = &state.fImage;
SkRect bitmapBounds;
image->getBounds(&bitmapBounds);
// For tiling modes, the bounds should be extended to include the bitmap,
// otherwise the bitmap gets clipped out and the shader is empty and awful.
// For clamp modes, we're only interested in the clip region, whether
// or not the main bitmap is in it.
SkShader::TileMode tileModes[2];
tileModes[0] = state.fImageTileModes[0];
tileModes[1] = state.fImageTileModes[1];
if (tileModes[0] != SkShader::kClamp_TileMode ||
tileModes[1] != SkShader::kClamp_TileMode) {
deviceBounds.join(bitmapBounds);
}
SkISize size = SkISize::Make(SkScalarRoundToInt(deviceBounds.width()),
SkScalarRoundToInt(deviceBounds.height()));
SkAutoTUnref<SkPDFDevice> patternDevice(
SkPDFDevice::CreateUnflipped(size, dpi, canon));
SkCanvas canvas(patternDevice.get());
SkRect patternBBox;
image->getBounds(&patternBBox);
// Translate the canvas so that the bitmap origin is at (0, 0).
canvas.translate(-deviceBounds.left(), -deviceBounds.top());
patternBBox.offset(-deviceBounds.left(), -deviceBounds.top());
// Undo the translation in the final matrix
finalMatrix.preTranslate(deviceBounds.left(), deviceBounds.top());
// If the bitmap is out of bounds (i.e. clamp mode where we only see the
// stretched sides), canvas will clip this out and the extraneous data
// won't be saved to the PDF.
canvas.drawBitmap(*image, 0, 0);
SkScalar width = SkIntToScalar(image->width());
SkScalar height = SkIntToScalar(image->height());
// Tiling is implied. First we handle mirroring.
if (tileModes[0] == SkShader::kMirror_TileMode) {
SkMatrix xMirror;
xMirror.setScale(-1, 1);
xMirror.postTranslate(2 * width, 0);
drawBitmapMatrix(&canvas, *image, xMirror);
patternBBox.fRight += width;
}
if (tileModes[1] == SkShader::kMirror_TileMode) {
SkMatrix yMirror;
yMirror.setScale(SK_Scalar1, -SK_Scalar1);
yMirror.postTranslate(0, 2 * height);
drawBitmapMatrix(&canvas, *image, yMirror);
patternBBox.fBottom += height;
}
if (tileModes[0] == SkShader::kMirror_TileMode &&
tileModes[1] == SkShader::kMirror_TileMode) {
SkMatrix mirror;
mirror.setScale(-1, -1);
mirror.postTranslate(2 * width, 2 * height);
drawBitmapMatrix(&canvas, *image, mirror);
}
// Then handle Clamping, which requires expanding the pattern canvas to
// cover the entire surfaceBBox.
// If both x and y are in clamp mode, we start by filling in the corners.
// (Which are just a rectangles of the corner colors.)
if (tileModes[0] == SkShader::kClamp_TileMode &&
tileModes[1] == SkShader::kClamp_TileMode) {
SkPaint paint;
SkRect rect;
rect = SkRect::MakeLTRB(deviceBounds.left(), deviceBounds.top(), 0, 0);
if (!rect.isEmpty()) {
paint.setColor(image->getColor(0, 0));
canvas.drawRect(rect, paint);
}
rect = SkRect::MakeLTRB(width, deviceBounds.top(),
deviceBounds.right(), 0);
if (!rect.isEmpty()) {
paint.setColor(image->getColor(image->width() - 1, 0));
canvas.drawRect(rect, paint);
}
rect = SkRect::MakeLTRB(width, height,
deviceBounds.right(), deviceBounds.bottom());
if (!rect.isEmpty()) {
paint.setColor(image->getColor(image->width() - 1,
image->height() - 1));
canvas.drawRect(rect, paint);
}
rect = SkRect::MakeLTRB(deviceBounds.left(), height,
0, deviceBounds.bottom());
if (!rect.isEmpty()) {
paint.setColor(image->getColor(0, image->height() - 1));
canvas.drawRect(rect, paint);
}
}
// Then expand the left, right, top, then bottom.
if (tileModes[0] == SkShader::kClamp_TileMode) {
SkIRect subset = SkIRect::MakeXYWH(0, 0, 1, image->height());
if (deviceBounds.left() < 0) {
SkBitmap left;
SkAssertResult(image->extractSubset(&left, subset));
SkMatrix leftMatrix;
leftMatrix.setScale(-deviceBounds.left(), 1);
leftMatrix.postTranslate(deviceBounds.left(), 0);
drawBitmapMatrix(&canvas, left, leftMatrix);
if (tileModes[1] == SkShader::kMirror_TileMode) {
leftMatrix.postScale(SK_Scalar1, -SK_Scalar1);
leftMatrix.postTranslate(0, 2 * height);
drawBitmapMatrix(&canvas, left, leftMatrix);
}
patternBBox.fLeft = 0;
}
if (deviceBounds.right() > width) {
SkBitmap right;
subset.offset(image->width() - 1, 0);
SkAssertResult(image->extractSubset(&right, subset));
SkMatrix rightMatrix;
rightMatrix.setScale(deviceBounds.right() - width, 1);
rightMatrix.postTranslate(width, 0);
drawBitmapMatrix(&canvas, right, rightMatrix);
if (tileModes[1] == SkShader::kMirror_TileMode) {
rightMatrix.postScale(SK_Scalar1, -SK_Scalar1);
rightMatrix.postTranslate(0, 2 * height);
drawBitmapMatrix(&canvas, right, rightMatrix);
}
patternBBox.fRight = deviceBounds.width();
}
}
if (tileModes[1] == SkShader::kClamp_TileMode) {
SkIRect subset = SkIRect::MakeXYWH(0, 0, image->width(), 1);
if (deviceBounds.top() < 0) {
SkBitmap top;
SkAssertResult(image->extractSubset(&top, subset));
SkMatrix topMatrix;
topMatrix.setScale(SK_Scalar1, -deviceBounds.top());
topMatrix.postTranslate(0, deviceBounds.top());
drawBitmapMatrix(&canvas, top, topMatrix);
if (tileModes[0] == SkShader::kMirror_TileMode) {
topMatrix.postScale(-1, 1);
topMatrix.postTranslate(2 * width, 0);
drawBitmapMatrix(&canvas, top, topMatrix);
}
patternBBox.fTop = 0;
}
if (deviceBounds.bottom() > height) {
SkBitmap bottom;
subset.offset(0, image->height() - 1);
SkAssertResult(image->extractSubset(&bottom, subset));
SkMatrix bottomMatrix;
bottomMatrix.setScale(SK_Scalar1, deviceBounds.bottom() - height);
bottomMatrix.postTranslate(0, height);
drawBitmapMatrix(&canvas, bottom, bottomMatrix);
if (tileModes[0] == SkShader::kMirror_TileMode) {
bottomMatrix.postScale(-1, 1);
bottomMatrix.postTranslate(2 * width, 0);
drawBitmapMatrix(&canvas, bottom, bottomMatrix);
}
patternBBox.fBottom = deviceBounds.height();
}
}
// Put the canvas into the pattern stream (fContent).
SkAutoTDelete<SkStreamAsset> content(patternDevice->content());
SkPDFImageShader* imageShader = new SkPDFImageShader(autoState->detach());
imageShader->setData(content.get());
SkAutoTUnref<SkPDFDict> resourceDict(
patternDevice->createResourceDict());
populate_tiling_pattern_dict(imageShader, patternBBox,
resourceDict.get(), finalMatrix);
imageShader->fShaderState->fImage.unlockPixels();
canon->addImageShader(imageShader);
return imageShader;
}
bool SkPDFShader::State::operator==(const SkPDFShader::State& b) const {
if (fType != b.fType ||
fCanvasTransform != b.fCanvasTransform ||
fShaderTransform != b.fShaderTransform ||
fBBox != b.fBBox) {
return false;
}
if (fType == SkShader::kNone_GradientType) {
if (fPixelGeneration != b.fPixelGeneration ||
fPixelGeneration == 0 ||
fImageTileModes[0] != b.fImageTileModes[0] ||
fImageTileModes[1] != b.fImageTileModes[1]) {
return false;
}
} else {
if (fInfo.fColorCount != b.fInfo.fColorCount ||
memcmp(fInfo.fColors, b.fInfo.fColors,
sizeof(SkColor) * fInfo.fColorCount) != 0 ||
memcmp(fInfo.fColorOffsets, b.fInfo.fColorOffsets,
sizeof(SkScalar) * fInfo.fColorCount) != 0 ||
fInfo.fPoint[0] != b.fInfo.fPoint[0] ||
fInfo.fTileMode != b.fInfo.fTileMode) {
return false;
}
switch (fType) {
case SkShader::kLinear_GradientType:
if (fInfo.fPoint[1] != b.fInfo.fPoint[1]) {
return false;
}
break;
case SkShader::kRadial_GradientType:
if (fInfo.fRadius[0] != b.fInfo.fRadius[0]) {
return false;
}
break;
case SkShader::kConical_GradientType:
if (fInfo.fPoint[1] != b.fInfo.fPoint[1] ||
fInfo.fRadius[0] != b.fInfo.fRadius[0] ||
fInfo.fRadius[1] != b.fInfo.fRadius[1]) {
return false;
}
break;
case SkShader::kSweep_GradientType:
case SkShader::kNone_GradientType:
case SkShader::kColor_GradientType:
break;
}
}
return true;
}
SkPDFShader::State::State(const SkShader& shader, const SkMatrix& canvasTransform,
const SkIRect& bbox, SkScalar rasterScale)
: fCanvasTransform(canvasTransform),
fBBox(bbox),
fPixelGeneration(0) {
fInfo.fColorCount = 0;
fInfo.fColors = nullptr;
fInfo.fColorOffsets = nullptr;
fShaderTransform = shader.getLocalMatrix();
fImageTileModes[0] = fImageTileModes[1] = SkShader::kClamp_TileMode;
fType = shader.asAGradient(&fInfo);
if (fType == SkShader::kNone_GradientType) {
SkMatrix matrix;
if (shader.isABitmap(&fImage, &matrix, fImageTileModes)) {
SkASSERT(matrix.isIdentity());
} else {
// Generic fallback for unsupported shaders:
// * allocate a bbox-sized bitmap
// * shade the whole area
// * use the result as a bitmap shader
// bbox is in device space. While that's exactly what we want for sizing our bitmap,
// we need to map it into shader space for adjustments (to match
// SkPDFImageShader::Create's behavior).
SkRect shaderRect = SkRect::Make(bbox);
if (!inverse_transform_bbox(canvasTransform, &shaderRect)) {
fImage.reset();
return;
}
// Clamp the bitmap size to about 1M pixels
static const SkScalar kMaxBitmapArea = 1024 * 1024;
SkScalar bitmapArea = rasterScale * bbox.width() * rasterScale * bbox.height();
if (bitmapArea > kMaxBitmapArea) {
rasterScale *= SkScalarSqrt(kMaxBitmapArea / bitmapArea);
}
SkISize size = SkISize::Make(SkScalarRoundToInt(rasterScale * bbox.width()),
SkScalarRoundToInt(rasterScale * bbox.height()));
SkSize scale = SkSize::Make(SkIntToScalar(size.width()) / shaderRect.width(),
SkIntToScalar(size.height()) / shaderRect.height());
fImage.allocN32Pixels(size.width(), size.height());
fImage.eraseColor(SK_ColorTRANSPARENT);
SkPaint p;
p.setShader(const_cast<SkShader*>(&shader));
SkCanvas canvas(fImage);
canvas.scale(scale.width(), scale.height());
canvas.translate(-shaderRect.x(), -shaderRect.y());
canvas.drawPaint(p);
fShaderTransform.setTranslate(shaderRect.x(), shaderRect.y());
fShaderTransform.preScale(1 / scale.width(), 1 / scale.height());
}
fPixelGeneration = fImage.getGenerationID();
} else {
AllocateGradientInfoStorage();
shader.asAGradient(&fInfo);
}
}
SkPDFShader::State::State(const SkPDFShader::State& other)
: fType(other.fType),
fCanvasTransform(other.fCanvasTransform),
fShaderTransform(other.fShaderTransform),
fBBox(other.fBBox)
{
// Only gradients supported for now, since that is all that is used.
// If needed, image state copy constructor can be added here later.
SkASSERT(fType != SkShader::kNone_GradientType);
if (fType != SkShader::kNone_GradientType) {
fInfo = other.fInfo;
AllocateGradientInfoStorage();
for (int i = 0; i < fInfo.fColorCount; i++) {
fInfo.fColors[i] = other.fInfo.fColors[i];
fInfo.fColorOffsets[i] = other.fInfo.fColorOffsets[i];
}
}
}
/**
* Create a copy of this gradient state with alpha assigned to RGB luminousity.
* Only valid for gradient states.
*/
SkPDFShader::State* SkPDFShader::State::CreateAlphaToLuminosityState() const {
SkASSERT(fType != SkShader::kNone_GradientType);
SkPDFShader::State* newState = new SkPDFShader::State(*this);
for (int i = 0; i < fInfo.fColorCount; i++) {
SkAlpha alpha = SkColorGetA(fInfo.fColors[i]);
newState->fInfo.fColors[i] = SkColorSetARGB(255, alpha, alpha, alpha);
}
return newState;
}
/**
* Create a copy of this gradient state with alpha set to fully opaque
* Only valid for gradient states.
*/
SkPDFShader::State* SkPDFShader::State::CreateOpaqueState() const {
SkASSERT(fType != SkShader::kNone_GradientType);
SkPDFShader::State* newState = new SkPDFShader::State(*this);
for (int i = 0; i < fInfo.fColorCount; i++) {
newState->fInfo.fColors[i] = SkColorSetA(fInfo.fColors[i],
SK_AlphaOPAQUE);
}
return newState;
}
/**
* Returns true if state is a gradient and the gradient has alpha.
*/
bool SkPDFShader::State::GradientHasAlpha() const {
if (fType == SkShader::kNone_GradientType) {
return false;
}
for (int i = 0; i < fInfo.fColorCount; i++) {
SkAlpha alpha = SkColorGetA(fInfo.fColors[i]);
if (alpha != SK_AlphaOPAQUE) {
return true;
}
}
return false;
}
void SkPDFShader::State::AllocateGradientInfoStorage() {
fColorData.set(sk_malloc_throw(
fInfo.fColorCount * (sizeof(SkColor) + sizeof(SkScalar))));
fInfo.fColors = reinterpret_cast<SkColor*>(fColorData.get());
fInfo.fColorOffsets =
reinterpret_cast<SkScalar*>(fInfo.fColors + fInfo.fColorCount);
}