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gecko-dev/gfx/thebes/gfxContext.cpp

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifdef _MSC_VER
#define _USE_MATH_DEFINES
#endif
#include <math.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#include "cairo.h"
#include "gfxContext.h"
#include "gfxColor.h"
#include "gfxMatrix.h"
#include "gfxASurface.h"
#include "gfxPattern.h"
#include "gfxPlatform.h"
#include "gfxTeeSurface.h"
#include "sampler.h"
using namespace mozilla;
using namespace mozilla::gfx;
/* This class lives on the stack and allows gfxContext users to easily, and
* performantly get a gfx::Pattern to use for drawing in their current context.
*/
class GeneralPattern
{
public:
GeneralPattern(gfxContext *aContext) : mContext(aContext), mPattern(NULL) {}
~GeneralPattern() { if (mPattern) { mPattern->~Pattern(); } }
operator mozilla::gfx::Pattern&()
{
gfxContext::AzureState &state = mContext->CurrentState();
if (state.pattern) {
return *state.pattern->GetPattern(mContext->mDT, state.patternTransformChanged ? &state.patternTransform : nsnull);
} else if (state.sourceSurface) {
Matrix transform = state.surfTransform;
if (state.patternTransformChanged) {
Matrix mat = mContext->mDT->GetTransform();
mat.Invert();
transform = mat * state.patternTransform * transform;
}
mPattern = new (mSurfacePattern.addr())
SurfacePattern(state.sourceSurface, EXTEND_CLAMP, transform);
return *mPattern;
} else {
mPattern = new (mColorPattern.addr())
ColorPattern(state.color);
return *mPattern;
}
}
private:
union {
mozilla::AlignedStorage2<mozilla::gfx::ColorPattern> mColorPattern;
mozilla::AlignedStorage2<mozilla::gfx::SurfacePattern> mSurfacePattern;
};
gfxContext *mContext;
Pattern *mPattern;
};
gfxContext::gfxContext(gfxASurface *surface)
: mRefCairo(NULL)
, mSurface(surface)
{
MOZ_COUNT_CTOR(gfxContext);
mCairo = cairo_create(surface->CairoSurface());
mFlags = surface->GetDefaultContextFlags();
if (mSurface->GetRotateForLandscape()) {
// Rotate page 90 degrees to draw landscape page on portrait paper
gfxIntSize size = mSurface->GetSize();
Translate(gfxPoint(0, size.width));
gfxMatrix matrix(0, -1,
1, 0,
0, 0);
Multiply(matrix);
}
}
gfxContext::gfxContext(DrawTarget *aTarget)
: mPathIsRect(false)
, mTransformChanged(false)
, mCairo(NULL)
, mRefCairo(NULL)
, mSurface(NULL)
, mFlags(0)
, mDT(aTarget)
, mOriginalDT(aTarget)
{
MOZ_COUNT_CTOR(gfxContext);
mStateStack.SetLength(1);
CurrentState().drawTarget = mDT;
mDT->SetTransform(Matrix());
}
gfxContext::~gfxContext()
{
if (mCairo) {
cairo_destroy(mCairo);
}
if (mRefCairo) {
cairo_destroy(mRefCairo);
}
if (mDT) {
for (int i = mStateStack.Length() - 1; i >= 0; i--) {
for (unsigned int c = 0; c < mStateStack[i].pushedClips.Length(); c++) {
mDT->PopClip();
}
if (mStateStack[i].clipWasReset) {
break;
}
}
mDT->Flush();
}
MOZ_COUNT_DTOR(gfxContext);
}
gfxASurface *
gfxContext::OriginalSurface()
{
return mSurface;
}
already_AddRefed<gfxASurface>
gfxContext::CurrentSurface(gfxFloat *dx, gfxFloat *dy)
{
if (mCairo) {
cairo_surface_t *s = cairo_get_group_target(mCairo);
if (s == mSurface->CairoSurface()) {
if (dx && dy)
cairo_surface_get_device_offset(s, dx, dy);
gfxASurface *ret = mSurface;
NS_ADDREF(ret);
return ret;
}
if (dx && dy)
cairo_surface_get_device_offset(s, dx, dy);
return gfxASurface::Wrap(s);
} else {
if (dx && dy) {
*dx = *dy = 0;
}
// An Azure context doesn't have a surface backing it.
return NULL;
}
}
cairo_t *
gfxContext::GetCairo()
{
if (mCairo) {
return mCairo;
}
if (mRefCairo) {
// Set transform!
return mRefCairo;
}
mRefCairo = cairo_create(gfxPlatform::GetPlatform()->ScreenReferenceSurface()->CairoSurface());
return mRefCairo;
}
void
gfxContext::Save()
{
if (mCairo) {
cairo_save(mCairo);
} else {
CurrentState().transform = mDT->GetTransform();
mStateStack.AppendElement(AzureState(CurrentState()));
CurrentState().clipWasReset = false;
CurrentState().pushedClips.Clear();
}
}
void
gfxContext::Restore()
{
if (mCairo) {
cairo_restore(mCairo);
} else {
for (unsigned int c = 0; c < CurrentState().pushedClips.Length(); c++) {
mDT->PopClip();
}
if (CurrentState().clipWasReset &&
CurrentState().drawTarget == mStateStack[mStateStack.Length() - 2].drawTarget) {
PushClipsToDT(mDT);
}
mStateStack.RemoveElementAt(mStateStack.Length() - 1);
if (mPathBuilder || mPath || mPathIsRect) {
// Support here isn't fully correct if the path is continued -after-
// the restore. We don't currently have users that do this and we should
// make sure there will not be any. Sadly we can't assert this easily.
mTransformChanged = true;
mPathTransform = mDT->GetTransform();
}
mDT = CurrentState().drawTarget;
mDT->SetTransform(CurrentState().transform);
}
}
// drawing
void
gfxContext::NewPath()
{
if (mCairo) {
cairo_new_path(mCairo);
} else {
mPath = NULL;
mPathBuilder = NULL;
mPathIsRect = false;
mTransformChanged = false;
}
}
void
gfxContext::ClosePath()
{
if (mCairo) {
cairo_close_path(mCairo);
} else {
EnsurePathBuilder();
mPathBuilder->Close();
}
}
already_AddRefed<gfxPath> gfxContext::CopyPath() const
{
if (mCairo) {
nsRefPtr<gfxPath> path = new gfxPath(cairo_copy_path(mCairo));
return path.forget();
} else {
// XXX - This is not yet supported for Azure.
return NULL;
}
}
void gfxContext::AppendPath(gfxPath* path)
{
if (mCairo) {
if (path->mPath->status == CAIRO_STATUS_SUCCESS && path->mPath->num_data != 0)
cairo_append_path(mCairo, path->mPath);
} else {
// XXX - This is not yet supported for Azure.
return;
}
}
gfxPoint
gfxContext::CurrentPoint()
{
if (mCairo) {
double x, y;
cairo_get_current_point(mCairo, &x, &y);
return gfxPoint(x, y);
} else {
EnsurePathBuilder();
return ThebesPoint(mPathBuilder->CurrentPoint());
}
}
void
gfxContext::Stroke()
{
if (mCairo) {
cairo_stroke_preserve(mCairo);
} else {
AzureState &state = CurrentState();
if (mPathIsRect) {
mDT->StrokeRect(mRect, GeneralPattern(this),
state.strokeOptions,
DrawOptions(1.0f, GetOp(), state.aaMode));
} else {
EnsurePath();
mDT->Stroke(mPath, GeneralPattern(this), state.strokeOptions,
DrawOptions(1.0f, GetOp(), state.aaMode));
}
}
}
void
gfxContext::Fill()
{
SAMPLE_LABEL("gfxContext", "Fill");
if (mCairo) {
cairo_fill_preserve(mCairo);
} else {
FillAzure(1.0f);
}
}
void
gfxContext::FillWithOpacity(gfxFloat aOpacity)
{
if (mCairo) {
// This method exists in the hope that one day cairo gets a direct
// API for this, and then we would change this method to use that
// API instead.
if (aOpacity != 1.0) {
gfxContextAutoSaveRestore saveRestore(this);
Clip();
Paint(aOpacity);
} else {
Fill();
}
} else {
FillAzure(Float(aOpacity));
}
}
void
gfxContext::MoveTo(const gfxPoint& pt)
{
if (mCairo) {
cairo_move_to(mCairo, pt.x, pt.y);
} else {
EnsurePathBuilder();
mPathBuilder->MoveTo(ToPoint(pt));
}
}
void
gfxContext::NewSubPath()
{
if (mCairo) {
cairo_new_sub_path(mCairo);
} else {
// XXX - This has no users, we should kill it, it should be equivelant to a
// MoveTo to the path's current point.
}
}
void
gfxContext::LineTo(const gfxPoint& pt)
{
if (mCairo) {
cairo_line_to(mCairo, pt.x, pt.y);
} else {
EnsurePathBuilder();
mPathBuilder->LineTo(ToPoint(pt));
}
}
void
gfxContext::CurveTo(const gfxPoint& pt1, const gfxPoint& pt2, const gfxPoint& pt3)
{
if (mCairo) {
cairo_curve_to(mCairo, pt1.x, pt1.y, pt2.x, pt2.y, pt3.x, pt3.y);
} else {
EnsurePathBuilder();
mPathBuilder->BezierTo(ToPoint(pt1), ToPoint(pt2), ToPoint(pt3));
}
}
void
gfxContext::QuadraticCurveTo(const gfxPoint& pt1, const gfxPoint& pt2)
{
if (mCairo) {
double cx, cy;
cairo_get_current_point(mCairo, &cx, &cy);
cairo_curve_to(mCairo,
(cx + pt1.x * 2.0) / 3.0,
(cy + pt1.y * 2.0) / 3.0,
(pt1.x * 2.0 + pt2.x) / 3.0,
(pt1.y * 2.0 + pt2.y) / 3.0,
pt2.x,
pt2.y);
} else {
EnsurePathBuilder();
mPathBuilder->QuadraticBezierTo(ToPoint(pt1), ToPoint(pt2));
}
}
void
gfxContext::Arc(const gfxPoint& center, gfxFloat radius,
gfxFloat angle1, gfxFloat angle2)
{
if (mCairo) {
cairo_arc(mCairo, center.x, center.y, radius, angle1, angle2);
} else {
EnsurePathBuilder();
mPathBuilder->Arc(ToPoint(center), Float(radius), Float(angle1), Float(angle2));
}
}
void
gfxContext::NegativeArc(const gfxPoint& center, gfxFloat radius,
gfxFloat angle1, gfxFloat angle2)
{
if (mCairo) {
cairo_arc_negative(mCairo, center.x, center.y, radius, angle1, angle2);
} else {
EnsurePathBuilder();
mPathBuilder->Arc(ToPoint(center), Float(radius), Float(angle2), Float(angle1));
}
}
void
gfxContext::Line(const gfxPoint& start, const gfxPoint& end)
{
if (mCairo) {
MoveTo(start);
LineTo(end);
} else {
EnsurePathBuilder();
mPathBuilder->MoveTo(ToPoint(start));
mPathBuilder->LineTo(ToPoint(end));
}
}
// XXX snapToPixels is only valid when snapping for filled
// rectangles and for even-width stroked rectangles.
// For odd-width stroked rectangles, we need to offset x/y by
// 0.5...
void
gfxContext::Rectangle(const gfxRect& rect, bool snapToPixels)
{
if (mCairo) {
if (snapToPixels) {
gfxRect snappedRect(rect);
if (UserToDevicePixelSnapped(snappedRect, true))
{
cairo_matrix_t mat;
cairo_get_matrix(mCairo, &mat);
cairo_identity_matrix(mCairo);
Rectangle(snappedRect);
cairo_set_matrix(mCairo, &mat);
return;
}
}
cairo_rectangle(mCairo, rect.X(), rect.Y(), rect.Width(), rect.Height());
} else {
Rect rec = ToRect(rect);
if (snapToPixels) {
gfxRect newRect(rect);
if (UserToDevicePixelSnapped(newRect, true)) {
gfxMatrix mat = ThebesMatrix(mDT->GetTransform());
mat.Invert();
// We need the user space rect.
rec = ToRect(mat.TransformBounds(newRect));
}
}
if (!mPathBuilder && !mPathIsRect) {
mPathIsRect = true;
mRect = rec;
return;
} else if (!mPathBuilder) {
EnsurePathBuilder();
}
mPathBuilder->MoveTo(rec.TopLeft());
mPathBuilder->LineTo(rec.TopRight());
mPathBuilder->LineTo(rec.BottomRight());
mPathBuilder->LineTo(rec.BottomLeft());
mPathBuilder->Close();
}
}
void
gfxContext::Ellipse(const gfxPoint& center, const gfxSize& dimensions)
{
gfxSize halfDim = dimensions / 2.0;
gfxRect r(center - gfxPoint(halfDim.width, halfDim.height), dimensions);
gfxCornerSizes c(halfDim, halfDim, halfDim, halfDim);
RoundedRectangle (r, c);
}
void
gfxContext::Polygon(const gfxPoint *points, PRUint32 numPoints)
{
if (mCairo) {
if (numPoints == 0)
return;
cairo_move_to(mCairo, points[0].x, points[0].y);
for (PRUint32 i = 1; i < numPoints; ++i) {
cairo_line_to(mCairo, points[i].x, points[i].y);
}
} else {
if (numPoints == 0) {
return;
}
EnsurePathBuilder();
mPathBuilder->MoveTo(ToPoint(points[0]));
for (PRUint32 i = 1; i < numPoints; i++) {
mPathBuilder->LineTo(ToPoint(points[i]));
}
}
}
void
gfxContext::DrawSurface(gfxASurface *surface, const gfxSize& size)
{
if (mCairo) {
cairo_save(mCairo);
cairo_set_source_surface(mCairo, surface->CairoSurface(), 0, 0);
cairo_new_path(mCairo);
// pixel-snap this
Rectangle(gfxRect(gfxPoint(0.0, 0.0), size), true);
cairo_fill(mCairo);
cairo_restore(mCairo);
} else {
// Lifetime needs to be limited here since we may wrap surface's data.
RefPtr<SourceSurface> surf =
gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
Rect rect(0, 0, Float(size.width), Float(size.height));
rect.Intersect(Rect(0, 0, Float(surf->GetSize().width), Float(surf->GetSize().height)));
// XXX - Should fix pixel snapping.
mDT->DrawSurface(surf, rect, rect);
}
}
// transform stuff
void
gfxContext::Translate(const gfxPoint& pt)
{
if (mCairo) {
cairo_translate(mCairo, pt.x, pt.y);
} else {
Matrix newMatrix = mDT->GetTransform();
ChangeTransform(newMatrix.Translate(Float(pt.x), Float(pt.y)));
}
}
void
gfxContext::Scale(gfxFloat x, gfxFloat y)
{
if (mCairo) {
cairo_scale(mCairo, x, y);
} else {
Matrix newMatrix = mDT->GetTransform();
ChangeTransform(newMatrix.Scale(Float(x), Float(y)));
}
}
void
gfxContext::Rotate(gfxFloat angle)
{
if (mCairo) {
cairo_rotate(mCairo, angle);
} else {
Matrix rotation = Matrix::Rotation(Float(angle));
ChangeTransform(rotation * mDT->GetTransform());
}
}
void
gfxContext::Multiply(const gfxMatrix& matrix)
{
if (mCairo) {
const cairo_matrix_t& mat = reinterpret_cast<const cairo_matrix_t&>(matrix);
cairo_transform(mCairo, &mat);
} else {
ChangeTransform(ToMatrix(matrix) * mDT->GetTransform());
}
}
void
gfxContext::SetMatrix(const gfxMatrix& matrix)
{
if (mCairo) {
const cairo_matrix_t& mat = reinterpret_cast<const cairo_matrix_t&>(matrix);
cairo_set_matrix(mCairo, &mat);
} else {
ChangeTransform(ToMatrix(matrix));
}
}
void
gfxContext::IdentityMatrix()
{
if (mCairo) {
cairo_identity_matrix(mCairo);
} else {
ChangeTransform(Matrix());
}
}
gfxMatrix
gfxContext::CurrentMatrix() const
{
if (mCairo) {
cairo_matrix_t mat;
cairo_get_matrix(mCairo, &mat);
return gfxMatrix(*reinterpret_cast<gfxMatrix*>(&mat));
} else {
return ThebesMatrix(mDT->GetTransform());
}
}
void
gfxContext::NudgeCurrentMatrixToIntegers()
{
if (mCairo) {
cairo_matrix_t mat;
cairo_get_matrix(mCairo, &mat);
gfxMatrix(*reinterpret_cast<gfxMatrix*>(&mat)).NudgeToIntegers();
cairo_set_matrix(mCairo, &mat);
} else {
gfxMatrix matrix = ThebesMatrix(mTransform);
matrix.NudgeToIntegers();
mTransform = ToMatrix(matrix);
}
}
gfxPoint
gfxContext::DeviceToUser(const gfxPoint& point) const
{
if (mCairo) {
gfxPoint ret = point;
cairo_device_to_user(mCairo, &ret.x, &ret.y);
return ret;
} else {
Matrix matrix = mDT->GetTransform();
matrix.Invert();
return ThebesPoint(matrix * ToPoint(point));
}
}
gfxSize
gfxContext::DeviceToUser(const gfxSize& size) const
{
if (mCairo) {
gfxSize ret = size;
cairo_device_to_user_distance(mCairo, &ret.width, &ret.height);
return ret;
} else {
Matrix matrix = mDT->GetTransform();
matrix.Invert();
return ThebesSize(matrix * ToSize(size));
}
}
gfxRect
gfxContext::DeviceToUser(const gfxRect& rect) const
{
if (mCairo) {
gfxRect ret = rect;
cairo_device_to_user(mCairo, &ret.x, &ret.y);
cairo_device_to_user_distance(mCairo, &ret.width, &ret.height);
return ret;
} else {
Matrix matrix = mDT->GetTransform();
matrix.Invert();
return ThebesRect(matrix.TransformBounds(ToRect(rect)));
}
}
gfxPoint
gfxContext::UserToDevice(const gfxPoint& point) const
{
if (mCairo) {
gfxPoint ret = point;
cairo_user_to_device(mCairo, &ret.x, &ret.y);
return ret;
} else {
return ThebesPoint(mDT->GetTransform() * ToPoint(point));
}
}
gfxSize
gfxContext::UserToDevice(const gfxSize& size) const
{
if (mCairo) {
gfxSize ret = size;
cairo_user_to_device_distance(mCairo, &ret.width, &ret.height);
return ret;
} else {
const Matrix &matrix = mDT->GetTransform();
gfxSize newSize = size;
newSize.width = newSize.width * matrix._11 + newSize.height * matrix._12;
newSize.height = newSize.width * matrix._21 + newSize.height * matrix._22;
return newSize;
}
}
gfxRect
gfxContext::UserToDevice(const gfxRect& rect) const
{
if (mCairo) {
double xmin = rect.X(), ymin = rect.Y(), xmax = rect.XMost(), ymax = rect.YMost();
double x[3], y[3];
x[0] = xmin; y[0] = ymax;
x[1] = xmax; y[1] = ymax;
x[2] = xmax; y[2] = ymin;
cairo_user_to_device(mCairo, &xmin, &ymin);
xmax = xmin;
ymax = ymin;
for (int i = 0; i < 3; i++) {
cairo_user_to_device(mCairo, &x[i], &y[i]);
xmin = NS_MIN(xmin, x[i]);
xmax = NS_MAX(xmax, x[i]);
ymin = NS_MIN(ymin, y[i]);
ymax = NS_MAX(ymax, y[i]);
}
return gfxRect(xmin, ymin, xmax - xmin, ymax - ymin);
} else {
const Matrix &matrix = mDT->GetTransform();
return ThebesRect(matrix.TransformBounds(ToRect(rect)));
}
}
bool
gfxContext::UserToDevicePixelSnapped(gfxRect& rect, bool ignoreScale) const
{
if (GetFlags() & FLAG_DISABLE_SNAPPING)
return false;
// if we're not at 1.0 scale, don't snap, unless we're
// ignoring the scale. If we're not -just- a scale,
// never snap.
const gfxFloat epsilon = 0.0000001;
#define WITHIN_E(a,b) (fabs((a)-(b)) < epsilon)
if (mCairo) {
cairo_matrix_t mat;
cairo_get_matrix(mCairo, &mat);
if (!ignoreScale &&
(!WITHIN_E(mat.xx,1.0) || !WITHIN_E(mat.yy,1.0) ||
!WITHIN_E(mat.xy,0.0) || !WITHIN_E(mat.yx,0.0)))
return false;
} else {
Matrix mat = mDT->GetTransform();
if (!ignoreScale &&
(!WITHIN_E(mat._11,1.0) || !WITHIN_E(mat._22,1.0) ||
!WITHIN_E(mat._12,0.0) || !WITHIN_E(mat._21,0.0)))
return false;
}
#undef WITHIN_E
gfxPoint p1 = UserToDevice(rect.TopLeft());
gfxPoint p2 = UserToDevice(rect.TopRight());
gfxPoint p3 = UserToDevice(rect.BottomRight());
// Check that the rectangle is axis-aligned. For an axis-aligned rectangle,
// two opposite corners define the entire rectangle. So check if
// the axis-aligned rectangle with opposite corners p1 and p3
// define an axis-aligned rectangle whose other corners are p2 and p4.
// We actually only need to check one of p2 and p4, since an affine
// transform maps parallelograms to parallelograms.
if (p2 == gfxPoint(p1.x, p3.y) || p2 == gfxPoint(p3.x, p1.y)) {
p1.Round();
p3.Round();
rect.MoveTo(gfxPoint(NS_MIN(p1.x, p3.x), NS_MIN(p1.y, p3.y)));
rect.SizeTo(gfxSize(NS_MAX(p1.x, p3.x) - rect.X(),
NS_MAX(p1.y, p3.y) - rect.Y()));
return true;
}
return false;
}
bool
gfxContext::UserToDevicePixelSnapped(gfxPoint& pt, bool ignoreScale) const
{
if (GetFlags() & FLAG_DISABLE_SNAPPING)
return false;
// if we're not at 1.0 scale, don't snap, unless we're
// ignoring the scale. If we're not -just- a scale,
// never snap.
const gfxFloat epsilon = 0.0000001;
#define WITHIN_E(a,b) (fabs((a)-(b)) < epsilon)
if (mCairo) {
cairo_matrix_t mat;
cairo_get_matrix(mCairo, &mat);
if (!ignoreScale &&
(!WITHIN_E(mat.xx,1.0) || !WITHIN_E(mat.yy,1.0) ||
!WITHIN_E(mat.xy,0.0) || !WITHIN_E(mat.yx,0.0)))
return false;
} else {
Matrix mat = mDT->GetTransform();
if (!ignoreScale &&
(!WITHIN_E(mat._11,1.0) || !WITHIN_E(mat._22,1.0) ||
!WITHIN_E(mat._12,0.0) || !WITHIN_E(mat._21,0.0)))
return false;
}
#undef WITHIN_E
pt = UserToDevice(pt);
pt.Round();
return true;
}
void
gfxContext::PixelSnappedRectangleAndSetPattern(const gfxRect& rect,
gfxPattern *pattern)
{
gfxRect r(rect);
// Bob attempts to pixel-snap the rectangle, and returns true if
// the snapping succeeds. If it does, we need to set up an
// identity matrix, because the rectangle given back is in device
// coordinates.
//
// We then have to call a translate to dr.pos afterwards, to make
// sure the image lines up in the right place with our pixel
// snapped rectangle.
//
// If snapping wasn't successful, we just translate to where the
// pattern would normally start (in app coordinates) and do the
// same thing.
Rectangle(r, true);
SetPattern(pattern);
}
void
gfxContext::SetAntialiasMode(AntialiasMode mode)
{
if (mCairo) {
if (mode == MODE_ALIASED) {
cairo_set_antialias(mCairo, CAIRO_ANTIALIAS_NONE);
} else if (mode == MODE_COVERAGE) {
cairo_set_antialias(mCairo, CAIRO_ANTIALIAS_DEFAULT);
}
} else {
if (mode == MODE_ALIASED) {
CurrentState().aaMode = AA_NONE;
} else if (mode == MODE_COVERAGE) {
CurrentState().aaMode = AA_SUBPIXEL;
}
}
}
gfxContext::AntialiasMode
gfxContext::CurrentAntialiasMode() const
{
if (mCairo) {
cairo_antialias_t aa = cairo_get_antialias(mCairo);
if (aa == CAIRO_ANTIALIAS_NONE)
return MODE_ALIASED;
return MODE_COVERAGE;
} else {
if (CurrentState().aaMode == AA_NONE) {
return MODE_ALIASED;
}
return MODE_COVERAGE;
}
}
void
gfxContext::SetDash(gfxLineType ltype)
{
static double dash[] = {5.0, 5.0};
static double dot[] = {1.0, 1.0};
switch (ltype) {
case gfxLineDashed:
SetDash(dash, 2, 0.0);
break;
case gfxLineDotted:
SetDash(dot, 2, 0.0);
break;
case gfxLineSolid:
default:
SetDash(nsnull, 0, 0.0);
break;
}
}
void
gfxContext::SetDash(gfxFloat *dashes, int ndash, gfxFloat offset)
{
if (mCairo) {
cairo_set_dash(mCairo, dashes, ndash, offset);
} else {
AzureState &state = CurrentState();
state.dashPattern.SetLength(ndash);
for (int i = 0; i < ndash; i++) {
state.dashPattern[i] = Float(dashes[i]);
}
state.strokeOptions.mDashLength = ndash;
state.strokeOptions.mDashOffset = Float(offset);
state.strokeOptions.mDashPattern = ndash ? state.dashPattern.Elements() : NULL;
}
}
bool
gfxContext::CurrentDash(FallibleTArray<gfxFloat>& dashes, gfxFloat* offset) const
{
if (mCairo) {
int count = cairo_get_dash_count(mCairo);
if (count <= 0 || !dashes.SetLength(count)) {
return false;
}
cairo_get_dash(mCairo, dashes.Elements(), offset);
return true;
} else {
const AzureState &state = CurrentState();
int count = state.strokeOptions.mDashLength;
if (count <= 0 || !dashes.SetLength(count)) {
return false;
}
for (int i = 0; i < count; i++) {
dashes[i] = state.dashPattern[i];
}
*offset = state.strokeOptions.mDashOffset;
return true;
}
}
gfxFloat
gfxContext::CurrentDashOffset() const
{
if (mCairo) {
if (cairo_get_dash_count(mCairo) <= 0) {
return 0.0;
}
gfxFloat offset;
cairo_get_dash(mCairo, NULL, &offset);
return offset;
} else {
return CurrentState().strokeOptions.mDashOffset;
}
}
void
gfxContext::SetLineWidth(gfxFloat width)
{
if (mCairo) {
cairo_set_line_width(mCairo, width);
} else {
CurrentState().strokeOptions.mLineWidth = Float(width);
}
}
gfxFloat
gfxContext::CurrentLineWidth() const
{
if (mCairo) {
return cairo_get_line_width(mCairo);
} else {
return CurrentState().strokeOptions.mLineWidth;
}
}
void
gfxContext::SetOperator(GraphicsOperator op)
{
if (mCairo) {
if (mFlags & FLAG_SIMPLIFY_OPERATORS) {
if (op != OPERATOR_SOURCE &&
op != OPERATOR_CLEAR &&
op != OPERATOR_OVER)
op = OPERATOR_OVER;
}
cairo_set_operator(mCairo, (cairo_operator_t)op);
} else {
if (op == OPERATOR_CLEAR) {
CurrentState().opIsClear = true;
return;
}
CurrentState().opIsClear = false;
CurrentState().op = CompositionOpForOp(op);
}
}
gfxContext::GraphicsOperator
gfxContext::CurrentOperator() const
{
if (mCairo) {
return (GraphicsOperator)cairo_get_operator(mCairo);
} else {
return ThebesOp(CurrentState().op);
}
}
void
gfxContext::SetLineCap(GraphicsLineCap cap)
{
if (mCairo) {
cairo_set_line_cap(mCairo, (cairo_line_cap_t)cap);
} else {
CurrentState().strokeOptions.mLineCap = ToCapStyle(cap);
}
}
gfxContext::GraphicsLineCap
gfxContext::CurrentLineCap() const
{
if (mCairo) {
return (GraphicsLineCap)cairo_get_line_cap(mCairo);
} else {
return ThebesLineCap(CurrentState().strokeOptions.mLineCap);
}
}
void
gfxContext::SetLineJoin(GraphicsLineJoin join)
{
if (mCairo) {
cairo_set_line_join(mCairo, (cairo_line_join_t)join);
} else {
CurrentState().strokeOptions.mLineJoin = ToJoinStyle(join);
}
}
gfxContext::GraphicsLineJoin
gfxContext::CurrentLineJoin() const
{
if (mCairo) {
return (GraphicsLineJoin)cairo_get_line_join(mCairo);
} else {
return ThebesLineJoin(CurrentState().strokeOptions.mLineJoin);
}
}
void
gfxContext::SetMiterLimit(gfxFloat limit)
{
if (mCairo) {
cairo_set_miter_limit(mCairo, limit);
} else {
CurrentState().strokeOptions.mMiterLimit = Float(limit);
}
}
gfxFloat
gfxContext::CurrentMiterLimit() const
{
if (mCairo) {
return cairo_get_miter_limit(mCairo);
} else {
return CurrentState().strokeOptions.mMiterLimit;
}
}
void
gfxContext::SetFillRule(FillRule rule)
{
if (mCairo) {
cairo_set_fill_rule(mCairo, (cairo_fill_rule_t)rule);
} else {
CurrentState().fillRule = rule == FILL_RULE_WINDING ? FILL_WINDING : FILL_EVEN_ODD;
}
}
gfxContext::FillRule
gfxContext::CurrentFillRule() const
{
if (mCairo) {
return (FillRule)cairo_get_fill_rule(mCairo);
} else {
return FILL_RULE_WINDING;
}
}
// clipping
void
gfxContext::Clip(const gfxRect& rect)
{
if (mCairo) {
cairo_new_path(mCairo);
cairo_rectangle(mCairo, rect.X(), rect.Y(), rect.Width(), rect.Height());
cairo_clip(mCairo);
} else {
AzureState::PushedClip clip = { NULL, ToRect(rect), mDT->GetTransform() };
CurrentState().pushedClips.AppendElement(clip);
mDT->PushClipRect(ToRect(rect));
NewPath();
}
}
void
gfxContext::Clip()
{
if (mCairo) {
cairo_clip_preserve(mCairo);
} else {
if (mPathIsRect && !mTransformChanged) {
AzureState::PushedClip clip = { NULL, mRect, mDT->GetTransform() };
CurrentState().pushedClips.AppendElement(clip);
mDT->PushClipRect(mRect);
} else {
EnsurePath();
mDT->PushClip(mPath);
AzureState::PushedClip clip = { mPath, Rect(), mDT->GetTransform() };
CurrentState().pushedClips.AppendElement(clip);
}
}
}
void
gfxContext::ResetClip()
{
if (mCairo) {
cairo_reset_clip(mCairo);
} else {
for (int i = mStateStack.Length() - 1; i >= 0; i--) {
for (unsigned int c = 0; c < mStateStack[i].pushedClips.Length(); c++) {
mDT->PopClip();
}
if (mStateStack[i].clipWasReset) {
break;
}
}
CurrentState().pushedClips.Clear();
CurrentState().clipWasReset = true;
}
}
void
gfxContext::UpdateSurfaceClip()
{
if (mCairo) {
NewPath();
// we paint an empty rectangle to ensure the clip is propagated to
// the destination surface
SetDeviceColor(gfxRGBA(0,0,0,0));
Rectangle(gfxRect(0,1,1,0));
Fill();
}
}
gfxRect
gfxContext::GetClipExtents()
{
if (mCairo) {
double xmin, ymin, xmax, ymax;
cairo_clip_extents(mCairo, &xmin, &ymin, &xmax, &ymax);
return gfxRect(xmin, ymin, xmax - xmin, ymax - ymin);
} else {
unsigned int lastReset = 0;
for (int i = mStateStack.Length() - 1; i > 0; i--) {
if (mStateStack[i].clipWasReset) {
lastReset = i;
}
}
Rect rect(0, 0, Float(mDT->GetSize().width), Float(mDT->GetSize().height));
for (unsigned int i = lastReset; i < mStateStack.Length(); i++) {
for (unsigned int c = 0; c < mStateStack[i].pushedClips.Length(); c++) {
AzureState::PushedClip &clip = mStateStack[i].pushedClips[c];
if (clip.path) {
Rect bounds = clip.path->GetBounds(clip.transform);
rect.IntersectRect(rect, bounds);
} else {
rect.IntersectRect(rect, clip.transform.TransformBounds(clip.rect));
}
}
}
if (rect.width == 0 || rect.height == 0) {
return gfxRect(0, 0, 0, 0);
}
Matrix mat = mDT->GetTransform();
mat.Invert();
rect = mat.TransformBounds(rect);
return ThebesRect(rect);
}
}
bool
gfxContext::ClipContainsRect(const gfxRect& aRect)
{
if (mCairo) {
cairo_rectangle_list_t *clip =
cairo_copy_clip_rectangle_list(mCairo);
bool result = false;
if (clip->status == CAIRO_STATUS_SUCCESS) {
for (int i = 0; i < clip->num_rectangles; i++) {
gfxRect rect(clip->rectangles[i].x, clip->rectangles[i].y,
clip->rectangles[i].width, clip->rectangles[i].height);
if (rect.Contains(aRect)) {
result = true;
break;
}
}
}
cairo_rectangle_list_destroy(clip);
return result;
} else {
unsigned int lastReset = 0;
for (int i = mStateStack.Length() - 2; i > 0; i--) {
if (mStateStack[i].clipWasReset) {
lastReset = i;
}
}
// Since we always return false when the clip list contains a
// non-rectangular clip or a non-rectilinear transform, our 'total' clip
// is always a rectangle if we hit the end of this function.
Rect clipBounds(0, 0, Float(mDT->GetSize().width), Float(mDT->GetSize().height));
for (unsigned int i = lastReset; i < mStateStack.Length(); i++) {
for (unsigned int c = 0; c < mStateStack[i].pushedClips.Length(); c++) {
AzureState::PushedClip &clip = mStateStack[i].pushedClips[c];
if (clip.path || !clip.transform.IsRectilinear()) {
// Cairo behavior is we return false if the clip contains a non-
// rectangle.
return false;
} else {
Rect clipRect = mTransform.TransformBounds(clip.rect);
clipBounds.IntersectRect(clipBounds, clipRect);
}
}
}
return clipBounds.Contains(ToRect(aRect));
}
}
// rendering sources
void
gfxContext::SetColor(const gfxRGBA& c)
{
if (mCairo) {
if (gfxPlatform::GetCMSMode() == eCMSMode_All) {
gfxRGBA cms;
gfxPlatform::TransformPixel(c, cms, gfxPlatform::GetCMSRGBTransform());
// Use the original alpha to avoid unnecessary float->byte->float
// conversion errors
cairo_set_source_rgba(mCairo, cms.r, cms.g, cms.b, c.a);
}
else
cairo_set_source_rgba(mCairo, c.r, c.g, c.b, c.a);
} else {
CurrentState().pattern = NULL;
CurrentState().sourceSurfCairo = NULL;
CurrentState().sourceSurface = NULL;
if (gfxPlatform::GetCMSMode() == eCMSMode_All) {
gfxRGBA cms;
gfxPlatform::TransformPixel(c, cms, gfxPlatform::GetCMSRGBTransform());
// Use the original alpha to avoid unnecessary float->byte->float
// conversion errors
CurrentState().color = ToColor(cms);
}
else
CurrentState().color = ToColor(c);
}
}
void
gfxContext::SetDeviceColor(const gfxRGBA& c)
{
if (mCairo) {
cairo_set_source_rgba(mCairo, c.r, c.g, c.b, c.a);
} else {
CurrentState().pattern = NULL;
CurrentState().sourceSurfCairo = NULL;
CurrentState().sourceSurface = NULL;
CurrentState().color = ToColor(c);
}
}
bool
gfxContext::GetDeviceColor(gfxRGBA& c)
{
if (mCairo) {
return cairo_pattern_get_rgba(cairo_get_source(mCairo),
&c.r,
&c.g,
&c.b,
&c.a) == CAIRO_STATUS_SUCCESS;
} else {
if (CurrentState().sourceSurface) {
return false;
}
if (CurrentState().pattern) {
gfxRGBA color;
return CurrentState().pattern->GetSolidColor(c);
}
c = ThebesRGBA(CurrentState().color);
return true;
}
}
void
gfxContext::SetSource(gfxASurface *surface, const gfxPoint& offset)
{
if (mCairo) {
NS_ASSERTION(surface->GetAllowUseAsSource(), "Surface not allowed to be used as source!");
cairo_set_source_surface(mCairo, surface->CairoSurface(), offset.x, offset.y);
} else {
CurrentState().surfTransform = Matrix(1.0f, 0, 0, 1.0f, Float(offset.x), Float(offset.y));
CurrentState().pattern = NULL;
CurrentState().patternTransformChanged = false;
// Keep the underlying cairo surface around while we keep the
// sourceSurface.
CurrentState().sourceSurfCairo = surface;
CurrentState().sourceSurface =
gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
}
}
void
gfxContext::SetPattern(gfxPattern *pattern)
{
if (mCairo) {
cairo_set_source(mCairo, pattern->CairoPattern());
} else {
CurrentState().sourceSurfCairo = NULL;
CurrentState().sourceSurface = NULL;
CurrentState().patternTransformChanged = false;
CurrentState().pattern = pattern;
}
}
already_AddRefed<gfxPattern>
gfxContext::GetPattern()
{
if (mCairo) {
cairo_pattern_t *pat = cairo_get_source(mCairo);
NS_ASSERTION(pat, "I was told this couldn't be null");
gfxPattern *wrapper = nsnull;
if (pat)
wrapper = new gfxPattern(pat);
else
wrapper = new gfxPattern(gfxRGBA(0,0,0,0));
NS_IF_ADDREF(wrapper);
return wrapper;
} else {
nsRefPtr<gfxPattern> pat;
AzureState &state = CurrentState();
if (state.pattern) {
pat = state.pattern;
} else if (state.sourceSurface) {
NS_ASSERTION(false, "Ugh, this isn't good.");
} else {
pat = new gfxPattern(ThebesRGBA(state.color));
}
return pat.forget();
}
}
// masking
void
gfxContext::Mask(gfxPattern *pattern)
{
if (mCairo) {
cairo_mask(mCairo, pattern->CairoPattern());
} else {
mDT->Mask(GeneralPattern(this), *pattern->GetPattern(mDT), DrawOptions(1.0f, CurrentState().op, CurrentState().aaMode));
}
}
void
gfxContext::Mask(gfxASurface *surface, const gfxPoint& offset)
{
SAMPLE_LABEL("gfxContext", "Mask");
if (mCairo) {
cairo_mask_surface(mCairo, surface->CairoSurface(), offset.x, offset.y);
} else {
// Lifetime needs to be limited here as we may simply wrap surface's data.
RefPtr<SourceSurface> sourceSurf =
gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
gfxPoint pt = surface->GetDeviceOffset();
mDT->Mask(GeneralPattern(this),
SurfacePattern(sourceSurf, EXTEND_CLAMP,
Matrix(1.0f, 0, 0, 1.0f, Float(offset.x - pt.x), Float(offset.y - pt.y))),
DrawOptions(1.0f, CurrentState().op, CurrentState().aaMode));
}
}
void
gfxContext::Paint(gfxFloat alpha)
{
SAMPLE_LABEL("gfxContext", "Paint");
if (mCairo) {
cairo_paint_with_alpha(mCairo, alpha);
} else {
AzureState &state = CurrentState();
Matrix mat = mDT->GetTransform();
mat.Invert();
Rect paintRect = mat.TransformBounds(Rect(Point(0, 0), Size(mDT->GetSize())));
if (state.opIsClear) {
mDT->ClearRect(paintRect);
} else {
mDT->FillRect(paintRect, GeneralPattern(this),
DrawOptions(Float(alpha), GetOp()));
}
}
}
// groups
void
gfxContext::PushGroup(gfxASurface::gfxContentType content)
{
if (mCairo) {
cairo_push_group_with_content(mCairo, (cairo_content_t) content);
} else {
RefPtr<DrawTarget> newDT =
mDT->CreateSimilarDrawTarget(mDT->GetSize(), gfxPlatform::GetPlatform()->Optimal2DFormatForContent(content));
Save();
CurrentState().drawTarget = newDT;
PushClipsToDT(newDT);
newDT->SetTransform(mDT->GetTransform());
mDT = newDT;
}
}
static gfxRect
GetRoundOutDeviceClipExtents(gfxContext* aCtx)
{
gfxContextMatrixAutoSaveRestore save(aCtx);
aCtx->IdentityMatrix();
gfxRect r = aCtx->GetClipExtents();
r.RoundOut();
return r;
}
/**
* Copy the contents of aSrc to aDest, translated by aTranslation.
*/
static void
CopySurface(gfxASurface* aSrc, gfxASurface* aDest, const gfxPoint& aTranslation)
{
cairo_t *cr = cairo_create(aDest->CairoSurface());
cairo_set_source_surface(cr, aSrc->CairoSurface(), aTranslation.x, aTranslation.y);
cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
cairo_paint(cr);
cairo_destroy(cr);
}
void
gfxContext::PushGroupAndCopyBackground(gfxASurface::gfxContentType content)
{
if (mCairo) {
if (content == gfxASurface::CONTENT_COLOR_ALPHA &&
!(GetFlags() & FLAG_DISABLE_COPY_BACKGROUND)) {
nsRefPtr<gfxASurface> s = CurrentSurface();
if ((s->GetAllowUseAsSource() || s->GetType() == gfxASurface::SurfaceTypeTee) &&
(s->GetContentType() == gfxASurface::CONTENT_COLOR ||
s->GetOpaqueRect().Contains(GetRoundOutDeviceClipExtents(this)))) {
cairo_push_group_with_content(mCairo, CAIRO_CONTENT_COLOR);
nsRefPtr<gfxASurface> d = CurrentSurface();
if (d->GetType() == gfxASurface::SurfaceTypeTee) {
NS_ASSERTION(s->GetType() == gfxASurface::SurfaceTypeTee, "Mismatched types");
nsAutoTArray<nsRefPtr<gfxASurface>,2> ss;
nsAutoTArray<nsRefPtr<gfxASurface>,2> ds;
static_cast<gfxTeeSurface*>(s.get())->GetSurfaces(&ss);
static_cast<gfxTeeSurface*>(d.get())->GetSurfaces(&ds);
NS_ASSERTION(ss.Length() == ds.Length(), "Mismatched lengths");
gfxPoint translation = d->GetDeviceOffset() - s->GetDeviceOffset();
for (PRUint32 i = 0; i < ss.Length(); ++i) {
CopySurface(ss[i], ds[i], translation);
}
} else {
CopySurface(s, d, gfxPoint(0, 0));
}
d->SetOpaqueRect(s->GetOpaqueRect());
return;
}
}
} else {
IntRect clipExtents;
if (mDT->GetFormat() != FORMAT_B8G8R8X8) {
gfxRect clipRect = GetRoundOutDeviceClipExtents(this);
clipExtents = IntRect(clipRect.x, clipRect.y, clipRect.width, clipRect.height);
}
if (mDT->GetFormat() == FORMAT_B8G8R8X8 ||
mDT->GetOpaqueRect().Contains(clipExtents)) {
DrawTarget *oldDT = mDT;
RefPtr<SourceSurface> source = mDT->Snapshot();
PushGroup(content);
Rect surfRect(0, 0, Float(mDT->GetSize().width), Float(mDT->GetSize().height));
Matrix oldTransform = mDT->GetTransform();
mDT->SetTransform(Matrix());
mDT->DrawSurface(source, surfRect, surfRect);
mDT->SetTransform(oldTransform);
mDT->SetOpaqueRect(oldDT->GetOpaqueRect());
return;
}
}
PushGroup(content);
}
already_AddRefed<gfxPattern>
gfxContext::PopGroup()
{
if (mCairo) {
cairo_pattern_t *pat = cairo_pop_group(mCairo);
gfxPattern *wrapper = new gfxPattern(pat);
cairo_pattern_destroy(pat);
NS_IF_ADDREF(wrapper);
return wrapper;
} else {
RefPtr<SourceSurface> src = mDT->Snapshot();
Restore();
Matrix mat = mDT->GetTransform();
mat.Invert();
nsRefPtr<gfxPattern> pat = new gfxPattern(src, mat);
return pat.forget();
}
}
void
gfxContext::PopGroupToSource()
{
if (mCairo) {
cairo_pop_group_to_source(mCairo);
} else {
RefPtr<SourceSurface> src = mDT->Snapshot();
Restore();
CurrentState().sourceSurfCairo = NULL;
CurrentState().sourceSurface = src;
CurrentState().pattern = NULL;
CurrentState().patternTransformChanged = false;
Matrix mat = mDT->GetTransform();
mat.Invert();
CurrentState().surfTransform = mat;
}
}
bool
gfxContext::PointInFill(const gfxPoint& pt)
{
if (mCairo) {
return cairo_in_fill(mCairo, pt.x, pt.y);
} else {
return mPath->ContainsPoint(ToPoint(pt), mTransform);
}
}
bool
gfxContext::PointInStroke(const gfxPoint& pt)
{
if (mCairo) {
return cairo_in_stroke(mCairo, pt.x, pt.y);
} else {
// XXX - Used by SVG, needs fixing.
return false;
}
}
gfxRect
gfxContext::GetUserPathExtent()
{
if (mCairo) {
double xmin, ymin, xmax, ymax;
cairo_path_extents(mCairo, &xmin, &ymin, &xmax, &ymax);
return gfxRect(xmin, ymin, xmax - xmin, ymax - ymin);
} else {
return ThebesRect(mPath->GetBounds());
}
}
gfxRect
gfxContext::GetUserFillExtent()
{
if (mCairo) {
double xmin, ymin, xmax, ymax;
cairo_fill_extents(mCairo, &xmin, &ymin, &xmax, &ymax);
return gfxRect(xmin, ymin, xmax - xmin, ymax - ymin);
} else {
return ThebesRect(mPath->GetBounds());
}
}
gfxRect
gfxContext::GetUserStrokeExtent()
{
if (mCairo) {
double xmin, ymin, xmax, ymax;
cairo_stroke_extents(mCairo, &xmin, &ymin, &xmax, &ymax);
return gfxRect(xmin, ymin, xmax - xmin, ymax - ymin);
} else {
return ThebesRect(mPath->GetStrokedBounds(CurrentState().strokeOptions, mTransform));
}
}
already_AddRefed<gfxFlattenedPath>
gfxContext::GetFlattenedPath()
{
if (mCairo) {
gfxFlattenedPath *path =
new gfxFlattenedPath(cairo_copy_path_flat(mCairo));
NS_IF_ADDREF(path);
return path;
} else {
// XXX - Used by SVG, needs fixing.
return NULL;
}
}
bool
gfxContext::HasError()
{
if (mCairo) {
return cairo_status(mCairo) != CAIRO_STATUS_SUCCESS;
} else {
// As far as this is concerned, an Azure context is never in error.
return false;
}
}
void
gfxContext::RoundedRectangle(const gfxRect& rect,
const gfxCornerSizes& corners,
bool draw_clockwise)
{
//
// For CW drawing, this looks like:
//
// ...******0** 1 C
// ****
// *** 2
// **
// *
// *
// 3
// *
// *
//
// Where 0, 1, 2, 3 are the control points of the Bezier curve for
// the corner, and C is the actual corner point.
//
// At the start of the loop, the current point is assumed to be
// the point adjacent to the top left corner on the top
// horizontal. Note that corner indices start at the top left and
// continue clockwise, whereas in our loop i = 0 refers to the top
// right corner.
//
// When going CCW, the control points are swapped, and the first
// corner that's drawn is the top left (along with the top segment).
//
// There is considerable latitude in how one chooses the four
// control points for a Bezier curve approximation to an ellipse.
// For the overall path to be continuous and show no corner at the
// endpoints of the arc, points 0 and 3 must be at the ends of the
// straight segments of the rectangle; points 0, 1, and C must be
// collinear; and points 3, 2, and C must also be collinear. This
// leaves only two free parameters: the ratio of the line segments
// 01 and 0C, and the ratio of the line segments 32 and 3C. See
// the following papers for extensive discussion of how to choose
// these ratios:
//
// Dokken, Tor, et al. "Good approximation of circles by
// curvature-continuous Bezier curves." Computer-Aided
// Geometric Design 7(1990) 33--41.
// Goldapp, Michael. "Approximation of circular arcs by cubic
// polynomials." Computer-Aided Geometric Design 8(1991) 227--238.
// Maisonobe, Luc. "Drawing an elliptical arc using polylines,
// quadratic, or cubic Bezier curves."
// http://www.spaceroots.org/documents/ellipse/elliptical-arc.pdf
//
// We follow the approach in section 2 of Goldapp (least-error,
// Hermite-type approximation) and make both ratios equal to
//
// 2 2 + n - sqrt(2n + 28)
// alpha = - * ---------------------
// 3 n - 4
//
// where n = 3( cbrt(sqrt(2)+1) - cbrt(sqrt(2)-1) ).
//
// This is the result of Goldapp's equation (10b) when the angle
// swept out by the arc is pi/2, and the parameter "a-bar" is the
// expression given immediately below equation (21).
//
// Using this value, the maximum radial error for a circle, as a
// fraction of the radius, is on the order of 0.2 x 10^-3.
// Neither Dokken nor Goldapp discusses error for a general
// ellipse; Maisonobe does, but his choice of control points
// follows different constraints, and Goldapp's expression for
// 'alpha' gives much smaller radial error, even for very flat
// ellipses, than Maisonobe's equivalent.
//
// For the various corners and for each axis, the sign of this
// constant changes, or it might be 0 -- it's multiplied by the
// appropriate multiplier from the list before using.
if (mCairo) {
const gfxFloat alpha = 0.55191497064665766025;
typedef struct { gfxFloat a, b; } twoFloats;
twoFloats cwCornerMults[4] = { { -1, 0 },
{ 0, -1 },
{ +1, 0 },
{ 0, +1 } };
twoFloats ccwCornerMults[4] = { { +1, 0 },
{ 0, -1 },
{ -1, 0 },
{ 0, +1 } };
twoFloats *cornerMults = draw_clockwise ? cwCornerMults : ccwCornerMults;
gfxPoint pc, p0, p1, p2, p3;
if (draw_clockwise)
cairo_move_to(mCairo, rect.X() + corners[NS_CORNER_TOP_LEFT].width, rect.Y());
else
cairo_move_to(mCairo, rect.X() + rect.Width() - corners[NS_CORNER_TOP_RIGHT].width, rect.Y());
NS_FOR_CSS_CORNERS(i) {
// the corner index -- either 1 2 3 0 (cw) or 0 3 2 1 (ccw)
mozilla::css::Corner c = mozilla::css::Corner(draw_clockwise ? ((i+1) % 4) : ((4-i) % 4));
// i+2 and i+3 respectively. These are used to index into the corner
// multiplier table, and were deduced by calculating out the long form
// of each corner and finding a pattern in the signs and values.
int i2 = (i+2) % 4;
int i3 = (i+3) % 4;
pc = rect.AtCorner(c);
if (corners[c].width > 0.0 && corners[c].height > 0.0) {
p0.x = pc.x + cornerMults[i].a * corners[c].width;
p0.y = pc.y + cornerMults[i].b * corners[c].height;
p3.x = pc.x + cornerMults[i3].a * corners[c].width;
p3.y = pc.y + cornerMults[i3].b * corners[c].height;
p1.x = p0.x + alpha * cornerMults[i2].a * corners[c].width;
p1.y = p0.y + alpha * cornerMults[i2].b * corners[c].height;
p2.x = p3.x - alpha * cornerMults[i3].a * corners[c].width;
p2.y = p3.y - alpha * cornerMults[i3].b * corners[c].height;
cairo_line_to (mCairo, p0.x, p0.y);
cairo_curve_to (mCairo,
p1.x, p1.y,
p2.x, p2.y,
p3.x, p3.y);
} else {
cairo_line_to (mCairo, pc.x, pc.y);
}
}
cairo_close_path (mCairo);
} else {
EnsurePathBuilder();
const gfxFloat alpha = 0.55191497064665766025;
typedef struct { gfxFloat a, b; } twoFloats;
twoFloats cwCornerMults[4] = { { -1, 0 },
{ 0, -1 },
{ +1, 0 },
{ 0, +1 } };
twoFloats ccwCornerMults[4] = { { +1, 0 },
{ 0, -1 },
{ -1, 0 },
{ 0, +1 } };
twoFloats *cornerMults = draw_clockwise ? cwCornerMults : ccwCornerMults;
gfxPoint pc, p0, p1, p2, p3;
if (draw_clockwise)
mPathBuilder->MoveTo(Point(Float(rect.X() + corners[NS_CORNER_TOP_LEFT].width), Float(rect.Y())));
else
mPathBuilder->MoveTo(Point(Float(rect.X() + rect.Width() - corners[NS_CORNER_TOP_RIGHT].width), Float(rect.Y())));
NS_FOR_CSS_CORNERS(i) {
// the corner index -- either 1 2 3 0 (cw) or 0 3 2 1 (ccw)
mozilla::css::Corner c = mozilla::css::Corner(draw_clockwise ? ((i+1) % 4) : ((4-i) % 4));
// i+2 and i+3 respectively. These are used to index into the corner
// multiplier table, and were deduced by calculating out the long form
// of each corner and finding a pattern in the signs and values.
int i2 = (i+2) % 4;
int i3 = (i+3) % 4;
pc = rect.AtCorner(c);
if (corners[c].width > 0.0 && corners[c].height > 0.0) {
p0.x = pc.x + cornerMults[i].a * corners[c].width;
p0.y = pc.y + cornerMults[i].b * corners[c].height;
p3.x = pc.x + cornerMults[i3].a * corners[c].width;
p3.y = pc.y + cornerMults[i3].b * corners[c].height;
p1.x = p0.x + alpha * cornerMults[i2].a * corners[c].width;
p1.y = p0.y + alpha * cornerMults[i2].b * corners[c].height;
p2.x = p3.x - alpha * cornerMults[i3].a * corners[c].width;
p2.y = p3.y - alpha * cornerMults[i3].b * corners[c].height;
mPathBuilder->LineTo(ToPoint(p0));
mPathBuilder->BezierTo(ToPoint(p1), ToPoint(p2), ToPoint(p3));
} else {
mPathBuilder->LineTo(ToPoint(pc));
}
}
mPathBuilder->Close();
}
}
#ifdef MOZ_DUMP_PAINTING
void
gfxContext::WriteAsPNG(const char* aFile)
{
nsRefPtr<gfxASurface> surf = CurrentSurface();
if (surf) {
surf->WriteAsPNG(aFile);
} else {
NS_WARNING("No surface found!");
}
}
void
gfxContext::DumpAsDataURL()
{
nsRefPtr<gfxASurface> surf = CurrentSurface();
if (surf) {
surf->DumpAsDataURL();
} else {
NS_WARNING("No surface found!");
}
}
void
gfxContext::CopyAsDataURL()
{
nsRefPtr<gfxASurface> surf = CurrentSurface();
if (surf) {
surf->CopyAsDataURL();
} else {
NS_WARNING("No surface found!");
}
}
#endif
void
gfxContext::EnsurePath()
{
if (mPathBuilder) {
mPath = mPathBuilder->Finish();
mPathBuilder = NULL;
}
if (mPath) {
if (mTransformChanged) {
Matrix mat = mDT->GetTransform();
mat.Invert();
mat = mPathTransform * mat;
mPathBuilder = mPath->TransformedCopyToBuilder(mat, CurrentState().fillRule);
mPath = mPathBuilder->Finish();
mPathBuilder = NULL;
mTransformChanged = false;
}
if (CurrentState().fillRule == mPath->GetFillRule()) {
return;
}
mPathBuilder = mPath->CopyToBuilder(CurrentState().fillRule);
mPath = mPathBuilder->Finish();
mPathBuilder = NULL;
return;
}
EnsurePathBuilder();
mPath = mPathBuilder->Finish();
mPathBuilder = NULL;
}
void
gfxContext::EnsurePathBuilder()
{
if (mPathBuilder) {
return;
}
if (mPath) {
mPathBuilder = mPath->CopyToBuilder(CurrentState().fillRule);
mPath = NULL;
}
mPathBuilder = mDT->CreatePathBuilder(CurrentState().fillRule);
if (mPathIsRect && !mTransformChanged) {
mPathBuilder->MoveTo(mRect.TopLeft());
mPathBuilder->LineTo(mRect.TopRight());
mPathBuilder->LineTo(mRect.BottomRight());
mPathBuilder->LineTo(mRect.BottomLeft());
mPathBuilder->Close();
} else if (mPathIsRect) {
mTransformChanged = false;
Matrix mat = mDT->GetTransform();
mat.Invert();
mat = mPathTransform * mat;
mPathBuilder->MoveTo(mat * mRect.TopLeft());
mPathBuilder->LineTo(mat * mRect.TopRight());
mPathBuilder->LineTo(mat * mRect.BottomRight());
mPathBuilder->LineTo(mat * mRect.BottomLeft());
mPathBuilder->Close();
}
mPathIsRect = false;
}
void
gfxContext::FillAzure(Float aOpacity)
{
AzureState &state = CurrentState();
CompositionOp op = GetOp();
if (mPathIsRect && !mTransformChanged) {
if (state.opIsClear) {
mDT->ClearRect(mRect);
} else if (op == OP_SOURCE) {
// Emulate cairo operator source which is bound by mask!
mDT->ClearRect(mRect);
mDT->FillRect(mRect, GeneralPattern(this), DrawOptions(aOpacity));
} else {
mDT->FillRect(mRect, GeneralPattern(this), DrawOptions(aOpacity, op, state.aaMode));
}
} else {
EnsurePath();
NS_ASSERTION(!state.opIsClear, "We shouldn't be clearing complex paths!");
mDT->Fill(mPath, GeneralPattern(this), DrawOptions(aOpacity, op, state.aaMode));
}
}
void
gfxContext::PushClipsToDT(DrawTarget *aDT)
{
// Tricky, we have to restore all clips -since the last time- the clip
// was reset. If we didn't reset the clip, just popping the clips we
// added was fine.
unsigned int lastReset = 0;
for (int i = mStateStack.Length() - 2; i > 0; i--) {
if (mStateStack[i].clipWasReset) {
lastReset = i;
}
}
// Don't need to save the old transform, we'll be setting a new one soon!
// Push all clips from the last state on the stack where the clip was
// reset to the clip before ours.
for (unsigned int i = lastReset; i < mStateStack.Length() - 1; i++) {
for (unsigned int c = 0; c < mStateStack[i].pushedClips.Length(); c++) {
aDT->SetTransform(mStateStack[i].pushedClips[c].transform);
if (mStateStack[i].pushedClips[c].path) {
aDT->PushClip(mStateStack[i].pushedClips[c].path);
} else {
aDT->PushClipRect(mStateStack[i].pushedClips[c].rect);
}
}
}
}
CompositionOp
gfxContext::GetOp()
{
if (CurrentState().op != OP_SOURCE) {
return CurrentState().op;
}
AzureState &state = CurrentState();
if (state.pattern) {
if (state.pattern->IsOpaque()) {
return OP_OVER;
} else {
return OP_SOURCE;
}
} else if (state.sourceSurface) {
if (state.sourceSurface->GetFormat() == FORMAT_B8G8R8X8) {
return OP_OVER;
} else {
return OP_SOURCE;
}
} else {
if (state.color.a > 0.999) {
return OP_OVER;
} else {
return OP_SOURCE;
}
}
}
/* SVG font code can change the transform after having set the pattern on the
* context. When the pattern is set it is in user space, if the transform is
* changed after doing so the pattern needs to be converted back into userspace.
* We just store the old pattern here so that we only do the work needed here
* if the pattern is actually used.
*/
void
gfxContext::ChangeTransform(const Matrix &aNewMatrix)
{
AzureState &state = CurrentState();
if ((state.pattern || state.sourceSurface)
&& !state.patternTransformChanged) {
state.patternTransform = mDT->GetTransform();
state.patternTransformChanged = true;
}
if (mPathBuilder || mPathIsRect) {
Matrix invMatrix = aNewMatrix;
invMatrix.Invert();
Matrix toNewUS = mDT->GetTransform() * invMatrix;
if (toNewUS.IsRectilinear() && mPathIsRect) {
mRect = toNewUS.TransformBounds(mRect);
} else if (mPathIsRect) {
mPathBuilder = mDT->CreatePathBuilder(CurrentState().fillRule);
mPathBuilder->MoveTo(toNewUS * mRect.TopLeft());
mPathBuilder->LineTo(toNewUS * mRect.TopRight());
mPathBuilder->LineTo(toNewUS * mRect.BottomRight());
mPathBuilder->LineTo(toNewUS * mRect.BottomLeft());
mPathBuilder->Close();
} else {
RefPtr<Path> path = mPathBuilder->Finish();
// Create path in device space.
mPathBuilder = path->TransformedCopyToBuilder(toNewUS);
}
// No need to consider the transform changed now!
mTransformChanged = false;
}
mDT->SetTransform(aNewMatrix);
}
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