/
CanvasRenderingContext2d.cc
executable file
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CanvasRenderingContext2d.cc
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//
// CanvasRenderingContext2d.cc
//
// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
//
#include <cmath>
#include <string.h>
#include <stdlib.h>
#include <limits>
#include <vector>
#include <algorithm>
#include "Canvas.h"
#include "Point.h"
#include "Image.h"
#include "ImageData.h"
#include "CanvasRenderingContext2d.h"
#include "CanvasGradient.h"
#include "CanvasPattern.h"
#ifdef HAVE_FREETYPE
#include "FontFace.h"
#endif
// 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 \
if (!info[0]->IsNumber() \
||!info[1]->IsNumber() \
||!info[2]->IsNumber() \
||!info[3]->IsNumber()) return; \
double x = info[0]->NumberValue(); \
double y = info[1]->NumberValue(); \
double width = info[2]->NumberValue(); \
double height = info[3]->NumberValue();
/*
* Text baselines.
*/
enum {
TEXT_BASELINE_ALPHABETIC
, TEXT_BASELINE_TOP
, TEXT_BASELINE_BOTTOM
, TEXT_BASELINE_MIDDLE
, TEXT_BASELINE_IDEOGRAPHIC
, TEXT_BASELINE_HANGING
};
#if HAVE_PANGO
/*
* State helper function
*/
void state_assign_fontFamily(canvas_state_t *state, const char *str) {
free(state->fontFamily);
state->fontFamily = strndup(str, 100);
}
/*
* 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)))
#endif
/*
* 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, "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, "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, "setLineDash", SetLineDash);
Nan::SetPrototypeMethod(ctor, "getLineDash", GetLineDash);
Nan::SetPrototypeMethod(ctor, "_setFont", SetFont);
#ifdef HAVE_FREETYPE
Nan::SetPrototypeMethod(ctor, "_setFontFace", SetFontFace);
#endif
Nan::SetPrototypeMethod(ctor, "_setFillColor", SetFillColor);
Nan::SetPrototypeMethod(ctor, "_setStrokeColor", SetStrokeColor);
Nan::SetPrototypeMethod(ctor, "_setFillPattern", SetFillPattern);
Nan::SetPrototypeMethod(ctor, "_setStrokePattern", SetStrokePattern);
Nan::SetPrototypeMethod(ctor, "_setTextBaseline", SetTextBaseline);
Nan::SetPrototypeMethod(ctor, "_setTextAlignment", SetTextAlignment);
Nan::SetAccessor(proto, Nan::New("patternQuality").ToLocalChecked(), GetPatternQuality, SetPatternQuality);
Nan::SetAccessor(proto, Nan::New("globalCompositeOperation").ToLocalChecked(), GetGlobalCompositeOperation, SetGlobalCompositeOperation);
Nan::SetAccessor(proto, Nan::New("globalAlpha").ToLocalChecked(), GetGlobalAlpha, SetGlobalAlpha);
Nan::SetAccessor(proto, Nan::New("shadowColor").ToLocalChecked(), GetShadowColor, SetShadowColor);
Nan::SetAccessor(proto, Nan::New("fillColor").ToLocalChecked(), GetFillColor);
Nan::SetAccessor(proto, Nan::New("strokeColor").ToLocalChecked(), GetStrokeColor);
Nan::SetAccessor(proto, Nan::New("miterLimit").ToLocalChecked(), GetMiterLimit, SetMiterLimit);
Nan::SetAccessor(proto, Nan::New("lineWidth").ToLocalChecked(), GetLineWidth, SetLineWidth);
Nan::SetAccessor(proto, Nan::New("lineCap").ToLocalChecked(), GetLineCap, SetLineCap);
Nan::SetAccessor(proto, Nan::New("lineJoin").ToLocalChecked(), GetLineJoin, SetLineJoin);
Nan::SetAccessor(proto, Nan::New("lineDashOffset").ToLocalChecked(), GetLineDashOffset, SetLineDashOffset);
Nan::SetAccessor(proto, Nan::New("shadowOffsetX").ToLocalChecked(), GetShadowOffsetX, SetShadowOffsetX);
Nan::SetAccessor(proto, Nan::New("shadowOffsetY").ToLocalChecked(), GetShadowOffsetY, SetShadowOffsetY);
Nan::SetAccessor(proto, Nan::New("shadowBlur").ToLocalChecked(), GetShadowBlur, SetShadowBlur);
Nan::SetAccessor(proto, Nan::New("antialias").ToLocalChecked(), GetAntiAlias, SetAntiAlias);
Nan::SetAccessor(proto, Nan::New("textDrawingMode").ToLocalChecked(), GetTextDrawingMode, SetTextDrawingMode);
Nan::SetAccessor(proto, Nan::New("filter").ToLocalChecked(), GetFilter, SetFilter);
Nan::Set(target, Nan::New("CanvasRenderingContext2d").ToLocalChecked(), ctor->GetFunction());
}
/*
* Create a cairo context.
*/
Context2d::Context2d(Canvas *canvas) {
_canvas = canvas;
_context = cairo_create(canvas->surface());
#if HAVE_PANGO
_layout = pango_cairo_create_layout(_context);
#endif
cairo_set_line_width(_context, 1);
state = states[stateno = 0] = (canvas_state_t *) malloc(sizeof(canvas_state_t));
state->shadowBlur = 0;
state->shadowOffsetX = state->shadowOffsetY = 0;
state->globalAlpha = 1;
state->textAlignment = -1;
state->fillPattern = state->strokePattern = NULL;
state->fillGradient = state->strokeGradient = NULL;
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->textDrawingMode = TEXT_DRAW_PATHS;
#if HAVE_PANGO
state->fontWeight = PANGO_WEIGHT_NORMAL;
state->fontStyle = PANGO_STYLE_NORMAL;
state->fontSize = 10;
state->fontFamily = NULL;
state_assign_fontFamily(state, "sans serif");
setFontFromState();
#endif
}
/*
* Destroy cairo context.
*/
Context2d::~Context2d() {
while(stateno >= 0) {
#if HAVE_PANGO
free(states[stateno]->fontFamily);
#endif
free(states[stateno--]);
}
#if HAVE_PANGO
g_object_unref(_layout);
#endif
cairo_destroy(_context);
}
/*
* Save cairo / canvas state.
*/
void
Context2d::save() {
cairo_save(_context);
saveState();
}
/*
* Restore cairo / canvas state.
*/
void
Context2d::restore() {
cairo_restore(_context);
restoreState();
}
/*
* Save the current state.
*/
void
Context2d::saveState() {
if (stateno == CANVAS_MAX_STATES) return;
states[++stateno] = (canvas_state_t *) malloc(sizeof(canvas_state_t));
memcpy(states[stateno], state, sizeof(canvas_state_t));
#if HAVE_PANGO
states[stateno]->fontFamily = strndup(state->fontFamily, 100);
#endif
state = states[stateno];
}
/*
* Restore state.
*/
void
Context2d::restoreState() {
if (0 == stateno) return;
// Olaf (2011-02-21): Free old state data
#if HAVE_PANGO
free(states[stateno]->fontFamily);
#endif
free(states[stateno]);
states[stateno] = NULL;
state = states[--stateno];
#if HAVE_PANGO
setFontFromState();
#endif
}
/*
* 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()) {
String::Utf8Value 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);
}
}
/*
* 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);
}
}
/*
* 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);
// 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 = info[0]->ToObject();
if (!Nan::New(Canvas::constructor)->HasInstance(obj))
return Nan::ThrowTypeError("Canvas expected");
Canvas *canvas = Nan::ObjectWrap::Unwrap<Canvas>(obj);
Context2d *context = new Context2d(canvas);
context->Wrap(info.This());
info.GetReturnValue().Set(info.This());
}
/*
* Create a new page.
*/
NAN_METHOD(Context2d::AddPage) {
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
if (!context->canvas()->isPDF()) {
return Nan::ThrowError("only PDF canvases support .nextPage()");
}
cairo_show_page(context->context());
return;
}
/*
* 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 = info[0]->ToObject();
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 srcStride = imageData->stride()
, dstStride = context->canvas()->stride();
int sx = 0
, sy = 0
, sw = 0
, sh = 0
, dx = info[1]->Int32Value()
, dy = info[2]->Int32Value()
, rows
, cols;
switch (info.Length()) {
// imageData, dx, dy
case 3:
// 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)(imageData->width(), context->canvas()->width - dx);
rows = (std::min)(imageData->height(), context->canvas()->height - dy);
break;
// imageData, dx, dy, sx, sy, sw, sh
case 7:
sx = info[3]->Int32Value();
sy = info[4]->Int32Value();
sw = info[5]->Int32Value();
sh = info[6]->Int32Value();
// 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;
// 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()->width - dx);
rows = (std::min)(sh, context->canvas()->height - dy);
break;
default:
return Nan::ThrowError("invalid arguments");
}
if (cols <= 0 || rows <= 0) return;
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;
}
cairo_surface_mark_dirty_rectangle(
context->canvas()->surface()
, dx
, dy
, cols
, rows);
}
/*
* 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 = info[0]->Int32Value();
int sy = info[1]->Int32Value();
int sw = info[2]->Int32Value();
int sh = info[3]->Int32Value();
if (!sw)
return Nan::ThrowError("IndexSizeError: The source width is 0.");
if (!sh)
return Nan::ThrowError("IndexSizeError: The source height is 0.");
// WebKit and Firefox have this behavior:
// Flip the coordinates so the origin is top/left-most:
if (sw < 0) {
sx += sw;
sw = -sw;
}
if (sh < 0) {
sy += sh;
sh = -sh;
}
if (sx + sw > canvas->width) sw = canvas->width - sx;
if (sy + sh > canvas->height) sh = canvas->height - sy;
// WebKit/moz functionality. node-canvas used to return in either case.
if (sw <= 0) sw = 1;
if (sh <= 0) sh = 1;
// Non-compliant. "Pixels outside the canvas must be returned as transparent
// black." This instead clips the returned array to the canvas area.
if (sx < 0) {
sw += sx;
sx = 0;
}
if (sy < 0) {
sh += sy;
sy = 0;
}
int size = sw * sh * 4;
int srcStride = canvas->stride();
int dstStride = sw * 4;
uint8_t *src = canvas->data();
#if NODE_MAJOR_VERSION == 0 && NODE_MINOR_VERSION <= 10
Local<Object> global = Context::GetCurrent()->Global();
Local<Int32> sizeHandle = Nan::New(size);
Local<Value> caargv[] = { sizeHandle };
Local<Object> clampedArray = global->Get(Nan::New("Uint8ClampedArray").ToLocalChecked()).As<Function>()->NewInstance(1, caargv);
#else
Local<ArrayBuffer> buffer = ArrayBuffer::New(Isolate::GetCurrent(), size);
Local<Uint8ClampedArray> clampedArray = Uint8ClampedArray::New(buffer, 0, size);
#endif
Nan::TypedArrayContents<uint8_t> typedArrayContents(clampedArray);
uint8_t* dst = *typedArrayContents;
// Normalize data (argb -> rgba)
for (int y = 0; y < sh; ++y) {
uint32_t *row = (uint32_t *)(src + srcStride * (y + sy));
for (int x = 0; x < sw; ++x) {
int bx = x * 4;
uint32_t *pixel = row + x + sx;
uint8_t a = *pixel >> 24;
uint8_t r = *pixel >> 16;
uint8_t g = *pixel >> 8;
uint8_t b = *pixel;
dst[bx + 3] = a;
// Performance optimization: fully transparent/opaque pixels can be
// processed more efficiently.
if (a == 0 || a == 255) {
dst[bx + 0] = r;
dst[bx + 1] = g;
dst[bx + 2] = b;
} else {
float alpha = (float)a / 255;
dst[bx + 0] = (int)((float)r / alpha);
dst[bx + 1] = (int)((float)g / alpha);
dst[bx + 2] = (int)((float)b / alpha);
}
}
dst += dstStride;
}
const int argc = 3;
Local<Int32> swHandle = Nan::New(sw);
Local<Int32> shHandle = Nan::New(sh);
Local<Value> argv[argc] = { clampedArray, swHandle, shHandle };
Local<Function> constructor = Nan::GetFunction(Nan::New(ImageData::constructor)).ToLocalChecked();
Local<Object> instance = Nan::NewInstance(constructor, argc, argv).ToLocalChecked();
info.GetReturnValue().Set(instance);
}
/*
* Draw image src image to the destination (context).
*
* - dx, dy
* - dx, dy, dw, dh
* - sx, sy, sw, sh, dx, dy, dw, dh
*
*/
NAN_METHOD(Context2d::DrawImage) {
if (info.Length() < 3)
return Nan::ThrowTypeError("invalid arguments");
if (!info[0]->IsObject()
|| !info[1]->IsNumber()
|| !info[2]->IsNumber())
return Nan::ThrowTypeError("Expected object, number and number");
float sx = 0
, sy = 0
, sw = 0
, sh = 0
, dx, dy, dw, dh;
cairo_surface_t *surface;
Local<Object> obj = info[0]->ToObject();
// Image
if (Nan::New(Image::constructor)->HasInstance(obj)) {
Image *img = Nan::ObjectWrap::Unwrap<Image>(obj);
if (!img->isComplete()) {
return Nan::ThrowError("Image given has not completed loading");
}
sw = img->width;
sh = img->height;
surface = img->surface();
// Canvas
} else if (Nan::New(Canvas::constructor)->HasInstance(obj)) {
Canvas *canvas = Nan::ObjectWrap::Unwrap<Canvas>(obj);
sw = canvas->width;
sh = canvas->height;
surface = canvas->surface();
// Invalid
} else {
return Nan::ThrowTypeError("Image or Canvas expected");
}
Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
cairo_t *ctx = context->context();
// Arguments
switch (info.Length()) {
// img, sx, sy, sw, sh, dx, dy, dw, dh
case 9:
sx = info[1]->NumberValue();
sy = info[2]->NumberValue();
sw = info[3]->NumberValue();
sh = info[4]->NumberValue();
dx = info[5]->NumberValue();
dy = info[6]->NumberValue();
dw = info[7]->NumberValue();
dh = info[8]->NumberValue();
break;
// img, dx, dy, dw, dh
case 5:
dx = info[1]->NumberValue();
dy = info[2]->NumberValue();
dw = info[3]->NumberValue();
dh = info[4]->NumberValue();
break;
// img, dx, dy
case 3:
dx = info[1]->NumberValue();
dy = info[2]->NumberValue();
dw = sw;
dh = sh;
break;