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CanvasRenderingContext2d.cc
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CanvasRenderingContext2d.cc
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// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
#include "CanvasRenderingContext2d.h"
#include <algorithm>
#include "backend/ImageBackend.h"
#include <cairo-pdf.h>
#include "Canvas.h"
#include "CanvasGradient.h"
#include "CanvasPattern.h"
#include <cmath>
#include <cstdlib>
#include "Image.h"
#include "ImageData.h"
#include <limits>
#include <map>
#include "Point.h"
#include <string>
#include "Util.h"
#include <vector>
using namespace v8;
// Windows doesn't support the C99 names for these
#ifdef _MSC_VER
#define isnan(x) _isnan(x)
#define isinf(x) (!_finite(x))
#endif
#ifndef isnan
#define isnan(x) std::isnan(x)
#define isinf(x) std::isinf(x)
#endif
Nan::Persistent<FunctionTemplate> Context2d::constructor;
/*
* Rectangle arg assertions.
*/
#define RECT_ARGS \
double args[4]; \
if(!checkArgs(info, args, 4)) \
return; \
double x = args[0]; \
double y = args[1]; \
double width = args[2]; \
double height = args[3];
/*
* Text baselines.
*/
enum {
TEXT_BASELINE_ALPHABETIC
, TEXT_BASELINE_TOP
, TEXT_BASELINE_BOTTOM
, TEXT_BASELINE_MIDDLE
, TEXT_BASELINE_IDEOGRAPHIC
, TEXT_BASELINE_HANGING
};
/*
* Simple helper macro for a rather verbose function call.
*/
#define PANGO_LAYOUT_GET_METRICS(LAYOUT) pango_context_get_metrics( \
pango_layout_get_context(LAYOUT), \
pango_layout_get_font_description(LAYOUT), \
pango_context_get_language(pango_layout_get_context(LAYOUT)))
inline static bool checkArgs(const Nan::FunctionCallbackInfo<Value> &info, double *args, int argsNum, int offset = 0){
int argsEnd = offset + argsNum;
bool areArgsValid = true;
for (int i = offset; i < argsEnd; i++) {
double val = Nan::To<double>(info[i]).FromMaybe(0);
if (areArgsValid) {
if (val != val ||
val == std::numeric_limits<double>::infinity() ||
val == -std::numeric_limits<double>::infinity()) {
// We should continue the loop instead of returning immediately
// See https://html.spec.whatwg.org/multipage/canvas.html
areArgsValid = false;
continue;
}
args[i - offset] = val;
}
}
return areArgsValid;
}
Nan::Persistent<Function> Context2d::_DOMMatrix;
Nan::Persistent<Function> Context2d::_parseFont;
/*
* Initialize Context2d.
*/
void
Context2d::Initialize(Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target) {
Nan::HandleScope scope;
// Constructor
Local<FunctionTemplate> ctor = Nan::New<FunctionTemplate>(Context2d::New);
constructor.Reset(ctor);
ctor->InstanceTemplate()->SetInternalFieldCount(1);
ctor->SetClassName(Nan::New("CanvasRenderingContext2D").ToLocalChecked());
// Prototype
Local<ObjectTemplate> proto = ctor->PrototypeTemplate();
Nan::SetPrototypeMethod(ctor, "drawImage", DrawImage);
Nan::SetPrototypeMethod(ctor, "putImageData", PutImageData);
Nan::SetPrototypeMethod(ctor, "getImageData", GetImageData);
Nan::SetPrototypeMethod(ctor, "createImageData", CreateImageData);
Nan::SetPrototypeMethod(ctor, "addPage", AddPage);
Nan::SetPrototypeMethod(ctor, "save", Save);
Nan::SetPrototypeMethod(ctor, "restore", Restore);
Nan::SetPrototypeMethod(ctor, "rotate", Rotate);
Nan::SetPrototypeMethod(ctor, "translate", Translate);
Nan::SetPrototypeMethod(ctor, "transform", Transform);
Nan::SetPrototypeMethod(ctor, "resetTransform", ResetTransform);
Nan::SetPrototypeMethod(ctor, "setTransform", SetTransform);
Nan::SetPrototypeMethod(ctor, "isPointInPath", IsPointInPath);
Nan::SetPrototypeMethod(ctor, "scale", Scale);
Nan::SetPrototypeMethod(ctor, "clip", Clip);
Nan::SetPrototypeMethod(ctor, "fill", Fill);
Nan::SetPrototypeMethod(ctor, "stroke", Stroke);
Nan::SetPrototypeMethod(ctor, "fillText", FillText);
Nan::SetPrototypeMethod(ctor, "strokeText", StrokeText);
Nan::SetPrototypeMethod(ctor, "fillRect", FillRect);
Nan::SetPrototypeMethod(ctor, "strokeRect", StrokeRect);
Nan::SetPrototypeMethod(ctor, "clearRect", ClearRect);
Nan::SetPrototypeMethod(ctor, "rect", Rect);
Nan::SetPrototypeMethod(ctor, "measureText", MeasureText);
Nan::SetPrototypeMethod(ctor, "moveTo", MoveTo);
Nan::SetPrototypeMethod(ctor, "lineTo", LineTo);
Nan::SetPrototypeMethod(ctor, "bezierCurveTo", BezierCurveTo);
Nan::SetPrototypeMethod(ctor, "quadraticCurveTo", QuadraticCurveTo);
Nan::SetPrototypeMethod(ctor, "beginPath", BeginPath);
Nan::SetPrototypeMethod(ctor, "closePath", ClosePath);
Nan::SetPrototypeMethod(ctor, "arc", Arc);
Nan::SetPrototypeMethod(ctor, "arcTo", ArcTo);
Nan::SetPrototypeMethod(ctor, "ellipse", Ellipse);
Nan::SetPrototypeMethod(ctor, "setLineDash", SetLineDash);
Nan::SetPrototypeMethod(ctor, "getLineDash", GetLineDash);
Nan::SetPrototypeMethod(ctor, "createPattern", CreatePattern);
Nan::SetPrototypeMethod(ctor, "createLinearGradient", CreateLinearGradient);
Nan::SetPrototypeMethod(ctor, "createRadialGradient", CreateRadialGradient);
SetProtoAccessor(proto, Nan::New("pixelFormat").ToLocalChecked(), GetFormat, NULL, ctor);
SetProtoAccessor(proto, Nan::New("patternQuality").ToLocalChecked(), GetPatternQuality, SetPatternQuality, ctor);
SetProtoAccessor(proto, Nan::New("imageSmoothingEnabled").ToLocalChecked(), GetImageSmoothingEnabled, SetImageSmoothingEnabled, ctor);
SetProtoAccessor(proto, Nan::New("globalCompositeOperation").ToLocalChecked(), GetGlobalCompositeOperation, SetGlobalCompositeOperation, ctor);
SetProtoAccessor(proto, Nan::New("globalAlpha").ToLocalChecked(), GetGlobalAlpha, SetGlobalAlpha, ctor);
SetProtoAccessor(proto, Nan::New("shadowColor").ToLocalChecked(), GetShadowColor, SetShadowColor, ctor);
SetProtoAccessor(proto, Nan::New("miterLimit").ToLocalChecked(), GetMiterLimit, SetMiterLimit, ctor);
SetProtoAccessor(proto, Nan::New("lineWidth").ToLocalChecked(), GetLineWidth, SetLineWidth, ctor);
SetProtoAccessor(proto, Nan::New("lineCap").ToLocalChecked(), GetLineCap, SetLineCap, ctor);
SetProtoAccessor(proto, Nan::New("lineJoin").ToLocalChecked(), GetLineJoin, SetLineJoin, ctor);
SetProtoAccessor(proto, Nan::New("lineDashOffset").ToLocalChecked(), GetLineDashOffset, SetLineDashOffset, ctor);
SetProtoAccessor(proto, Nan::New("shadowOffsetX").ToLocalChecked(), GetShadowOffsetX, SetShadowOffsetX, ctor);
SetProtoAccessor(proto, Nan::New("shadowOffsetY").ToLocalChecked(), GetShadowOffsetY, SetShadowOffsetY, ctor);
SetProtoAccessor(proto, Nan::New("shadowBlur").ToLocalChecked(), GetShadowBlur, SetShadowBlur, ctor);
SetProtoAccessor(proto, Nan::New("antialias").ToLocalChecked(), GetAntiAlias, SetAntiAlias, ctor);
SetProtoAccessor(proto, Nan::New("textDrawingMode").ToLocalChecked(), GetTextDrawingMode, SetTextDrawingMode, ctor);
SetProtoAccessor(proto, Nan::New("quality").ToLocalChecked(), GetQuality, SetQuality, ctor);
SetProtoAccessor(proto, Nan::New("currentTransform").ToLocalChecked(), GetCurrentTransform, SetCurrentTransform, ctor);
SetProtoAccessor(proto, Nan::New("fillStyle").ToLocalChecked(), GetFillStyle, SetFillStyle, ctor);
SetProtoAccessor(proto, Nan::New("strokeStyle").ToLocalChecked(), GetStrokeStyle, SetStrokeStyle, ctor);
SetProtoAccessor(proto, Nan::New("font").ToLocalChecked(), GetFont, SetFont, ctor);
SetProtoAccessor(proto, Nan::New("textBaseline").ToLocalChecked(), GetTextBaseline, SetTextBaseline, ctor);
SetProtoAccessor(proto, Nan::New("textAlign").ToLocalChecked(), GetTextAlign, SetTextAlign, ctor);
Local<Context> ctx = Nan::GetCurrentContext();
Nan::Set(target, Nan::New("CanvasRenderingContext2d").ToLocalChecked(), ctor->GetFunction(ctx).ToLocalChecked());
Nan::Set(target, Nan::New("CanvasRenderingContext2dInit").ToLocalChecked(), Nan::New<Function>(SaveExternalModules));
}
/*
* Create a cairo context.
*/
Context2d::Context2d(Canvas *canvas) {
_canvas = canvas;
_context = canvas->createCairoContext();
_layout = pango_cairo_create_layout(_context);
state = states[stateno = 0] = (canvas_state_t *) malloc(sizeof(canvas_state_t));
resetState(true);
}
/*
* Destroy cairo context.
*/
Context2d::~Context2d() {
while(stateno >= 0) {
pango_font_description_free(states[stateno]->fontDescription);
free(states[stateno--]);
}
g_object_unref(_layout);
cairo_destroy(_context);
_resetPersistentHandles();
}
/*
* Reset canvas state.
*/
void Context2d::resetState(bool init) {
if (!init) {
pango_font_description_free(state->fontDescription);
}
state->shadowBlur = 0;
state->shadowOffsetX = state->shadowOffsetY = 0;
state->globalAlpha = 1;
state->textAlignment = -1;
state->fillPattern = nullptr;
state->strokePattern = nullptr;
state->fillGradient = nullptr;
state->strokeGradient = nullptr;
state->textBaseline = TEXT_BASELINE_ALPHABETIC;
rgba_t transparent = { 0, 0, 0, 1 };
rgba_t transparent_black = { 0, 0, 0, 0 };
state->fill = transparent;
state->stroke = transparent;
state->shadow = transparent_black;
state->patternQuality = CAIRO_FILTER_GOOD;
state->imageSmoothingEnabled = true;
state->textDrawingMode = TEXT_DRAW_PATHS;
state->fontDescription = pango_font_description_from_string("sans");
pango_font_description_set_absolute_size(state->fontDescription, 10 * PANGO_SCALE);
pango_layout_set_font_description(_layout, state->fontDescription);
_resetPersistentHandles();
}
void Context2d::_resetPersistentHandles() {
_fillStyle.Reset();
_strokeStyle.Reset();
_font.Reset();
_textBaseline.Reset();
_textAlign.Reset();
}
/*
* Save cairo / canvas state.
*/
void
Context2d::save() {
if (stateno < CANVAS_MAX_STATES) {
cairo_save(_context);
states[++stateno] = (canvas_state_t *) malloc(sizeof(canvas_state_t));
memcpy(states[stateno], state, sizeof(canvas_state_t));
states[stateno]->fontDescription = pango_font_description_copy(states[stateno-1]->fontDescription);
state = states[stateno];
}
}
/*
* Restore cairo / canvas state.
*/
void
Context2d::restore() {
if (stateno > 0) {
cairo_restore(_context);
pango_font_description_free(states[stateno]->fontDescription);
free(states[stateno]);
states[stateno] = NULL;
state = states[--stateno];
pango_layout_set_font_description(_layout, state->fontDescription);
}
}
/*
* Save flat path.
*/
void
Context2d::savePath() {
_path = cairo_copy_path_flat(_context);
cairo_new_path(_context);
}
/*
* Restore flat path.
*/
void
Context2d::restorePath() {
cairo_new_path(_context);
cairo_append_path(_context, _path);
cairo_path_destroy(_path);
}
/*
* Create temporary surface for gradient or pattern transparency
*/
cairo_pattern_t*
create_transparent_gradient(cairo_pattern_t *source, float alpha) {
double x0;
double y0;
double x1;
double y1;
double r0;
double r1;
int count;
int i;
double offset;
double r;
double g;
double b;
double a;
cairo_pattern_t *newGradient;
cairo_pattern_type_t type = cairo_pattern_get_type(source);
cairo_pattern_get_color_stop_count(source, &count);
if (type == CAIRO_PATTERN_TYPE_LINEAR) {
cairo_pattern_get_linear_points (source, &x0, &y0, &x1, &y1);
newGradient = cairo_pattern_create_linear(x0, y0, x1, y1);
} else if (type == CAIRO_PATTERN_TYPE_RADIAL) {
cairo_pattern_get_radial_circles(source, &x0, &y0, &r0, &x1, &y1, &r1);
newGradient = cairo_pattern_create_radial(x0, y0, r0, x1, y1, r1);
} else {
Nan::ThrowError("Unexpected gradient type");
return NULL;
}
for ( i = 0; i < count; i++ ) {
cairo_pattern_get_color_stop_rgba(source, i, &offset, &r, &g, &b, &a);
cairo_pattern_add_color_stop_rgba(newGradient, offset, r, g, b, a * alpha);
}
return newGradient;
}
cairo_pattern_t*
create_transparent_pattern(cairo_pattern_t *source, float alpha) {
cairo_surface_t *surface;
cairo_pattern_get_surface(source, &surface);
int width = cairo_image_surface_get_width(surface);
int height = cairo_image_surface_get_height(surface);
cairo_surface_t *mask_surface = cairo_image_surface_create(
CAIRO_FORMAT_ARGB32,
width,
height);
cairo_t *mask_context = cairo_create(mask_surface);
if (cairo_status(mask_context) != CAIRO_STATUS_SUCCESS) {
Nan::ThrowError("Failed to initialize context");
return NULL;
}
cairo_set_source(mask_context, source);
cairo_paint_with_alpha(mask_context, alpha);
cairo_destroy(mask_context);
cairo_pattern_t* newPattern = cairo_pattern_create_for_surface(mask_surface);
cairo_surface_destroy(mask_surface);
return newPattern;
}
/*
* Fill and apply shadow.
*/
void
Context2d::setFillRule(v8::Local<v8::Value> value) {
cairo_fill_rule_t rule = CAIRO_FILL_RULE_WINDING;
if (value->IsString()) {
Nan::Utf8String str(value);
if (std::strcmp(*str, "evenodd") == 0) {
rule = CAIRO_FILL_RULE_EVEN_ODD;
}
}
cairo_set_fill_rule(_context, rule);
}
void
Context2d::fill(bool preserve) {
cairo_pattern_t *new_pattern;
if (state->fillPattern) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_pattern(state->fillPattern, state->globalAlpha);
if (new_pattern == NULL) {
// failed to allocate; Nan::ThrowError has already been called, so return from this fn.
return;
}
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_set_source(_context, state->fillPattern);
}
repeat_type_t repeat = Pattern::get_repeat_type_for_cairo_pattern(state->fillPattern);
if (NO_REPEAT == repeat) {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_NONE);
} else {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_REPEAT);
}
} else if (state->fillGradient) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_gradient(state->fillGradient, state->globalAlpha);
if (new_pattern == NULL) {
// failed to recognize gradient; Nan::ThrowError has already been called, so return from this fn.
return;
}
cairo_pattern_set_filter(new_pattern, state->patternQuality);
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_pattern_set_filter(state->fillGradient, state->patternQuality);
cairo_set_source(_context, state->fillGradient);
}
} else {
setSourceRGBA(state->fill);
}
if (preserve) {
hasShadow()
? shadow(cairo_fill_preserve)
: cairo_fill_preserve(_context);
} else {
hasShadow()
? shadow(cairo_fill)
: cairo_fill(_context);
}
// Notify backend that the Cairo surface has got a painting operation
canvas()->backend()->onPaint();
}
/*
* Stroke and apply shadow.
*/
void
Context2d::stroke(bool preserve) {
cairo_pattern_t *new_pattern;
if (state->strokePattern) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_pattern(state->strokePattern, state->globalAlpha);
if (new_pattern == NULL) {
// failed to allocate; Nan::ThrowError has already been called, so return from this fn.
return;
}
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_set_source(_context, state->strokePattern);
}
repeat_type_t repeat = Pattern::get_repeat_type_for_cairo_pattern(state->strokePattern);
if (NO_REPEAT == repeat) {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_NONE);
} else {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_REPEAT);
}
} else if (state->strokeGradient) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_gradient(state->strokeGradient, state->globalAlpha);
if (new_pattern == NULL) {
// failed to recognize gradient; Nan::ThrowError has already been called, so return from this fn.
return;
}
cairo_pattern_set_filter(new_pattern, state->patternQuality);
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_pattern_set_filter(state->strokeGradient, state->patternQuality);
cairo_set_source(_context, state->strokeGradient);
}
} else {
setSourceRGBA(state->stroke);
}
if (preserve) {
hasShadow()
? shadow(cairo_stroke_preserve)
: cairo_stroke_preserve(_context);
} else {
hasShadow()
? shadow(cairo_stroke)
: cairo_stroke(_context);
}
// Notify backend that the Cairo surface has got a painting operation
canvas()->backend()->onPaint();
}
/*
* Apply shadow with the given draw fn.
*/
void
Context2d::shadow(void (fn)(cairo_t *cr)) {
cairo_path_t *path = cairo_copy_path_flat(_context);
cairo_save(_context);
// shadowOffset is unaffected by current transform
cairo_matrix_t path_matrix;
cairo_get_matrix(_context, &path_matrix);
cairo_identity_matrix(_context);
// Apply shadow
cairo_push_group(_context);
// No need to invoke blur if shadowBlur is 0
if (state->shadowBlur) {
// find out extent of path
double x1, y1, x2, y2;
if (fn == cairo_fill || fn == cairo_fill_preserve) {
cairo_fill_extents(_context, &x1, &y1, &x2, &y2);
} else {
cairo_stroke_extents(_context, &x1, &y1, &x2, &y2);
}
// create new image surface that size + padding for blurring
double dx = x2-x1, dy = y2-y1;
cairo_user_to_device_distance(_context, &dx, &dy);
int pad = state->shadowBlur * 2;
cairo_surface_t *shadow_surface = cairo_image_surface_create(
CAIRO_FORMAT_ARGB32,
dx + 2 * pad,
dy + 2 * pad);
cairo_t *shadow_context = cairo_create(shadow_surface);
// transform path to the right place
cairo_translate(shadow_context, pad-x1, pad-y1);
cairo_transform(shadow_context, &path_matrix);
// set lineCap lineJoin lineDash
cairo_set_line_cap(shadow_context, cairo_get_line_cap(_context));
cairo_set_line_join(shadow_context, cairo_get_line_join(_context));
double offset;
int dashes = cairo_get_dash_count(_context);
std::vector<double> a(dashes);
cairo_get_dash(_context, a.data(), &offset);
cairo_set_dash(shadow_context, a.data(), dashes, offset);
// draw the path and blur
cairo_set_line_width(shadow_context, cairo_get_line_width(_context));
cairo_new_path(shadow_context);
cairo_append_path(shadow_context, path);
setSourceRGBA(shadow_context, state->shadow);
fn(shadow_context);
blur(shadow_surface, state->shadowBlur);
// paint to original context
cairo_set_source_surface(_context, shadow_surface,
x1 - pad + state->shadowOffsetX + 1,
y1 - pad + state->shadowOffsetY + 1);
cairo_paint(_context);
cairo_destroy(shadow_context);
cairo_surface_destroy(shadow_surface);
} else {
// Offset first, then apply path's transform
cairo_translate(
_context
, state->shadowOffsetX
, state->shadowOffsetY);
cairo_transform(_context, &path_matrix);
// Apply shadow
cairo_new_path(_context);
cairo_append_path(_context, path);
setSourceRGBA(state->shadow);
fn(_context);
}
// Paint the shadow
cairo_pop_group_to_source(_context);
cairo_paint(_context);
// Restore state
cairo_restore(_context);
cairo_new_path(_context);
cairo_append_path(_context, path);
fn(_context);
cairo_path_destroy(path);
}
/*
* Set source RGBA for the current context
*/
void
Context2d::setSourceRGBA(rgba_t color) {
setSourceRGBA(_context, color);
}
/*
* Set source RGBA
*/
void
Context2d::setSourceRGBA(cairo_t *ctx, rgba_t color) {
cairo_set_source_rgba(
ctx
, color.r
, color.g
, color.b
, color.a * state->globalAlpha);
}
/*
* Check if the context has a drawable shadow.
*/
bool
Context2d::hasShadow() {
return state->shadow.a
&& (state->shadowBlur || state->shadowOffsetX || state->shadowOffsetY);
}
/*
* Blur the given surface with the given radius.
*/
void
Context2d::blur(cairo_surface_t *surface, int radius) {
// Steve Hanov, 2009
// Released into the public domain.
radius = radius * 0.57735f + 0.5f;
// get width, height
int width = cairo_image_surface_get_width( surface );
int height = cairo_image_surface_get_height( surface );
unsigned* precalc =
(unsigned*)malloc(width*height*sizeof(unsigned));
cairo_surface_flush( surface );
unsigned char* src = cairo_image_surface_get_data( surface );
double mul=1.f/((radius*2)*(radius*2));
int channel;
// The number of times to perform the averaging. According to wikipedia,
// three iterations is good enough to pass for a gaussian.
const int MAX_ITERATIONS = 3;
int iteration;
for ( iteration = 0; iteration < MAX_ITERATIONS; iteration++ ) {
for( channel = 0; channel < 4; channel++ ) {
int x,y;
// precomputation step.
unsigned char* pix = src;
unsigned* pre = precalc;
pix += channel;
for (y=0;y<height;y++) {
for (x=0;x<width;x++) {
int tot=pix[0];
if (x>0) tot+=pre[-1];
if (y>0) tot+=pre[-width];
if (x>0 && y>0) tot-=pre[-width-1];
*pre++=tot;
pix += 4;
}
}
// blur step.
pix = src + (int)radius * width * 4 + (int)radius * 4 + channel;
for (y=radius;y<height-radius;y++) {
for (x=radius;x<width-radius;x++) {
int l = x < radius ? 0 : x - radius;
int t = y < radius ? 0 : y - radius;
int r = x + radius >= width ? width - 1 : x + radius;
int b = y + radius >= height ? height - 1 : y + radius;
int tot = precalc[r+b*width] + precalc[l+t*width] -
precalc[l+b*width] - precalc[r+t*width];
*pix=(unsigned char)(tot*mul);
pix += 4;
}
pix += (int)radius * 2 * 4;
}
}
}
cairo_surface_mark_dirty(surface);
free(precalc);
}
/*
* Initialize a new Context2d with the given canvas.
*/
NAN_METHOD(Context2d::New) {
if (!info.IsConstructCall()) {
return Nan::ThrowTypeError("Class constructors cannot be invoked without 'new'");
}
if (!info[0]->IsObject())
return Nan::ThrowTypeError("Canvas expected");
Local<Object> obj = Nan::To<Object>(info[0]).ToLocalChecked();
if (!Nan::New(Canvas::constructor)->HasInstance(obj))
return Nan::ThrowTypeError("Canvas expected");
Canvas *canvas = Nan::ObjectWrap::Unwrap<Canvas>(obj);
bool isImageBackend = canvas->backend()->getName() == "image";
if (isImageBackend) {
cairo_format_t format = ImageBackend::DEFAULT_FORMAT;
if (info[1]->IsObject()) {
Local<Object> ctxAttributes = Nan::To<Object>(info[1]).ToLocalChecked();
Local<Value> pixelFormat = Nan::Get(ctxAttributes, Nan::New("pixelFormat").ToLocalChecked()).ToLocalChecked();
if (pixelFormat->IsString()) {
Nan::Utf8String utf8PixelFormat(pixelFormat);
if (!strcmp(*utf8PixelFormat, "RGBA32")) format = CAIRO_FORMAT_ARGB32;
else if (!strcmp(*utf8PixelFormat, "RGB24")) format = CAIRO_FORMAT_RGB24;
else if (!strcmp(*utf8PixelFormat, "A8")) format = CAIRO_FORMAT_A8;
else if (!strcmp(*utf8PixelFormat, "RGB16_565")) format = CAIRO_FORMAT_RGB16_565;
else if (!strcmp(*utf8PixelFormat, "A1")) format = CAIRO_FORMAT_A1;
#ifdef CAIRO_FORMAT_RGB30
else if (!strcmp(utf8PixelFormat, "RGB30")) format = CAIRO_FORMAT_RGB30;
#endif
}
// alpha: false forces use of RGB24
Local<Value> alpha = Nan::Get(ctxAttributes, Nan::New("alpha").ToLocalChecked()).ToLocalChecked();
if (alpha->IsBoolean() && !Nan::To<bool>(alpha).FromMaybe(false)) {
format = CAIRO_FORMAT_RGB24;
}
}
static_cast<ImageBackend*>(canvas->backend())->setFormat(format);
}
Context2d *context = new Context2d(canvas);
context->Wrap(info.This());
info.GetReturnValue().Set(info.This());
}
/*
* Save some external modules as private references.
*/
NAN_METHOD(Context2d::SaveExternalModules) {
_DOMMatrix.Reset(Nan::To<Function>(info[0]).ToLocalChecked());
_parseFont.Reset(Nan::To<Function>(info[1]).ToLocalChecked());
}
/*
* Get format (string).
*/
NAN_GETTER(Context2d::GetFormat) {
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
std::string pixelFormatString;
switch (context->canvas()->backend()->getFormat()) {
case CAIRO_FORMAT_ARGB32: pixelFormatString = "RGBA32"; break;
case CAIRO_FORMAT_RGB24: pixelFormatString = "RGB24"; break;
case CAIRO_FORMAT_A8: pixelFormatString = "A8"; break;
case CAIRO_FORMAT_A1: pixelFormatString = "A1"; break;
case CAIRO_FORMAT_RGB16_565: pixelFormatString = "RGB16_565"; break;
#ifdef CAIRO_FORMAT_RGB30
case CAIRO_FORMAT_RGB30: pixelFormatString = "RGB30"; break;
#endif
default: return info.GetReturnValue().SetNull();
}
info.GetReturnValue().Set(Nan::New<String>(pixelFormatString).ToLocalChecked());
}
/*
* Create a new page.
*/
NAN_METHOD(Context2d::AddPage) {
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
if (context->canvas()->backend()->getName() != "pdf") {
return Nan::ThrowError("only PDF canvases support .addPage()");
}
cairo_show_page(context->context());
int width = Nan::To<int32_t>(info[0]).FromMaybe(0);
int height = Nan::To<int32_t>(info[1]).FromMaybe(0);
if (width < 1) width = context->canvas()->getWidth();
if (height < 1) height = context->canvas()->getHeight();
cairo_pdf_surface_set_size(context->canvas()->surface(), width, height);
// Notify backend that the Cairo surface has got a painting operation
context->canvas()->backend()->onPaint();
}
/*
* Put image data.
*
* - imageData, dx, dy
* - imageData, dx, dy, sx, sy, sw, sh
*
*/
NAN_METHOD(Context2d::PutImageData) {
if (!info[0]->IsObject())
return Nan::ThrowTypeError("ImageData expected");
Local<Object> obj = Nan::To<Object>(info[0]).ToLocalChecked();
if (!Nan::New(ImageData::constructor)->HasInstance(obj))
return Nan::ThrowTypeError("ImageData expected");
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
ImageData *imageData = Nan::ObjectWrap::Unwrap<ImageData>(obj);
uint8_t *src = imageData->data();
uint8_t *dst = context->canvas()->data();
int dstStride = context->canvas()->stride();
int Bpp = dstStride / context->canvas()->getWidth();
int srcStride = Bpp * imageData->width();
int sx = 0
, sy = 0
, sw = 0
, sh = 0
, dx = Nan::To<int32_t>(info[1]).FromMaybe(0)
, dy = Nan::To<int32_t>(info[2]).FromMaybe(0)
, rows
, cols;
switch (info.Length()) {
// imageData, dx, dy
case 3:
sw = imageData->width();
sh = imageData->height();
break;
// imageData, dx, dy, sx, sy, sw, sh
case 7:
sx = Nan::To<int32_t>(info[3]).FromMaybe(0);
sy = Nan::To<int32_t>(info[4]).FromMaybe(0);
sw = Nan::To<int32_t>(info[5]).FromMaybe(0);
sh = Nan::To<int32_t>(info[6]).FromMaybe(0);
// fix up negative height, width
if (sw < 0) sx += sw, sw = -sw;
if (sh < 0) sy += sh, sh = -sh;
// clamp the left edge
if (sx < 0) sw += sx, sx = 0;
if (sy < 0) sh += sy, sy = 0;
// clamp the right edge
if (sx + sw > imageData->width()) sw = imageData->width() - sx;
if (sy + sh > imageData->height()) sh = imageData->height() - sy;
// start destination at source offset
dx += sx;
dy += sy;
break;
default:
return Nan::ThrowError("invalid arguments");
}
// chop off outlying source data
if (dx < 0) sw += dx, sx -= dx, dx = 0;
if (dy < 0) sh += dy, sy -= dy, dy = 0;
// clamp width at canvas size
// Need to wrap std::min calls using parens to prevent macro expansion on
// windows. See http://stackoverflow.com/questions/5004858/stdmin-gives-error
cols = (std::min)(sw, context->canvas()->getWidth() - dx);
rows = (std::min)(sh, context->canvas()->getHeight() - dy);
if (cols <= 0 || rows <= 0) return;
switch (context->canvas()->backend()->getFormat()) {
case CAIRO_FORMAT_ARGB32: {
src += sy * srcStride + sx * 4;
dst += dstStride * dy + 4 * dx;
for (int y = 0; y < rows; ++y) {
uint8_t *dstRow = dst;
uint8_t *srcRow = src;
for (int x = 0; x < cols; ++x) {
// rgba
uint8_t r = *srcRow++;
uint8_t g = *srcRow++;
uint8_t b = *srcRow++;
uint8_t a = *srcRow++;
// argb
// performance optimization: fully transparent/opaque pixels can be
// processed more efficiently.
if (a == 0) {
*dstRow++ = 0;
*dstRow++ = 0;
*dstRow++ = 0;
*dstRow++ = 0;
} else if (a == 255) {
*dstRow++ = b;
*dstRow++ = g;
*dstRow++ = r;
*dstRow++ = a;
} else {
float alpha = (float)a / 255;
*dstRow++ = b * alpha;
*dstRow++ = g * alpha;
*dstRow++ = r * alpha;
*dstRow++ = a;
}
}
dst += dstStride;
src += srcStride;
}
break;
}
case CAIRO_FORMAT_RGB24: {
src += sy * srcStride + sx * 4;
dst += dstStride * dy + 4 * dx;
for (int y = 0; y < rows; ++y) {
uint8_t *dstRow = dst;
uint8_t *srcRow = src;
for (int x = 0; x < cols; ++x) {
// rgba
uint8_t r = *srcRow++;
uint8_t g = *srcRow++;
uint8_t b = *srcRow++;
srcRow++;
// argb
*dstRow++ = b;
*dstRow++ = g;
*dstRow++ = r;
*dstRow++ = 255;
}
dst += dstStride;
src += srcStride;
}
break;
}
case CAIRO_FORMAT_A8: {
src += sy * srcStride + sx;
dst += dstStride * dy + dx;
if (srcStride == dstStride && cols == dstStride) {
// fast path: strides are the same and doing a full-width put
memcpy(dst, src, cols * rows);
} else {
for (int y = 0; y < rows; ++y) {
memcpy(dst, src, cols);
dst += dstStride;
src += srcStride;
}
}
break;
}
case CAIRO_FORMAT_A1: {
// TODO Should this be totally packed, or maintain a stride divisible by 4?
Nan::ThrowError("putImageData for CANVAS_FORMAT_A1 is not yet implemented");
break;
}
case CAIRO_FORMAT_RGB16_565: {
src += sy * srcStride + sx * 2;
dst += dstStride * dy + 2 * dx;
for (int y = 0; y < rows; ++y) {
memcpy(dst, src, cols * 2);
dst += dstStride;
src += srcStride;
}
break;
}
#ifdef CAIRO_FORMAT_RGB30
case CAIRO_FORMAT_RGB30: {
// TODO
Nan::ThrowError("putImageData for CANVAS_FORMAT_RGB30 is not yet implemented");
break;
}
#endif
default: {
Nan::ThrowError("Invalid pixel format");
break;
}
}
cairo_surface_mark_dirty_rectangle(
context->canvas()->surface()
, dx
, dy
, cols
, rows);
// Notify backend that the Cairo surface has got a painting operation
context->canvas()->backend()->onPaint();
}
/*
* Get image data.
*
* - sx, sy, sw, sh
*
*/
NAN_METHOD(Context2d::GetImageData) {
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
Canvas *canvas = context->canvas();
int sx = Nan::To<int32_t>(info[0]).FromMaybe(0);
int sy = Nan::To<int32_t>(info[1]).FromMaybe(0);
int sw = Nan::To<int32_t>(info[2]).FromMaybe(0);
int sh = Nan::To<int32_t>(info[3]).FromMaybe(0);
if (!sw)
return Nan::ThrowError("IndexSizeError: The source width is 0.");
if (!sh)
return Nan::ThrowError("IndexSizeError: The source height is 0.");
int width = canvas->getWidth();
int height = canvas->getHeight();
if (!width)
return Nan::ThrowTypeError("Canvas width is 0");