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CanvasRenderingContext2d.cc
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// Copyright (c) 2010 LearnBoost <[email protected]>
#include "CanvasRenderingContext2d.h"
#include <algorithm>
#include "backend/ImageBackend.h"
#include <cairo-pdf.h>
#include "Canvas.h"
#include "CanvasGradient.h"
#include "CanvasPattern.h"
#include "InstanceData.h"
#include "FontParser.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>
/*
* 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];
constexpr double twoPi = M_PI * 2.;
/*
* 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 Napi::CallbackInfo&info, double *args, int argsNum, int offset = 0){
Napi::Env env = info.Env();
int argsEnd = std::min(9, offset + argsNum);
bool areArgsValid = true;
napi_value argv[9];
size_t argc = 9;
napi_get_cb_info(env, static_cast<napi_callback_info>(info), &argc, argv, nullptr, nullptr);
for (int i = offset; i < argsEnd; i++) {
napi_valuetype type;
double val = 0;
napi_typeof(env, argv[i], &type);
if (type == napi_number) {
// fast path
napi_get_value_double(env, argv[i], &val);
} else {
napi_value num;
if (napi_coerce_to_number(env, argv[i], &num) == napi_ok) {
napi_get_value_double(env, num, &val);
}
}
if (areArgsValid) {
if (!std::isfinite(val)) {
// 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;
}
/*
* Initialize Context2d.
*/
void
Context2d::Initialize(Napi::Env& env, Napi::Object& exports) {
Napi::HandleScope scope(env);
InstanceData* data = env.GetInstanceData<InstanceData>();
Napi::Function ctor = DefineClass(env, "CanvasRenderingContext2D", {
InstanceMethod<&Context2d::DrawImage>("drawImage", napi_default_method),
InstanceMethod<&Context2d::PutImageData>("putImageData", napi_default_method),
InstanceMethod<&Context2d::GetImageData>("getImageData", napi_default_method),
InstanceMethod<&Context2d::CreateImageData>("createImageData", napi_default_method),
InstanceMethod<&Context2d::AddPage>("addPage", napi_default_method),
InstanceMethod<&Context2d::Save>("save", napi_default_method),
InstanceMethod<&Context2d::Restore>("restore", napi_default_method),
InstanceMethod<&Context2d::Rotate>("rotate", napi_default_method),
InstanceMethod<&Context2d::Translate>("translate", napi_default_method),
InstanceMethod<&Context2d::Transform>("transform", napi_default_method),
InstanceMethod<&Context2d::GetTransform>("getTransform", napi_default_method),
InstanceMethod<&Context2d::ResetTransform>("resetTransform", napi_default_method),
InstanceMethod<&Context2d::SetTransform>("setTransform", napi_default_method),
InstanceMethod<&Context2d::IsPointInPath>("isPointInPath", napi_default_method),
InstanceMethod<&Context2d::Scale>("scale", napi_default_method),
InstanceMethod<&Context2d::Clip>("clip", napi_default_method),
InstanceMethod<&Context2d::Fill>("fill", napi_default_method),
InstanceMethod<&Context2d::Stroke>("stroke", napi_default_method),
InstanceMethod<&Context2d::FillText>("fillText", napi_default_method),
InstanceMethod<&Context2d::StrokeText>("strokeText", napi_default_method),
InstanceMethod<&Context2d::FillRect>("fillRect", napi_default_method),
InstanceMethod<&Context2d::StrokeRect>("strokeRect", napi_default_method),
InstanceMethod<&Context2d::ClearRect>("clearRect", napi_default_method),
InstanceMethod<&Context2d::Rect>("rect", napi_default_method),
InstanceMethod<&Context2d::RoundRect>("roundRect", napi_default_method),
InstanceMethod<&Context2d::MeasureText>("measureText", napi_default_method),
InstanceMethod<&Context2d::MoveTo>("moveTo", napi_default_method),
InstanceMethod<&Context2d::LineTo>("lineTo", napi_default_method),
InstanceMethod<&Context2d::BezierCurveTo>("bezierCurveTo", napi_default_method),
InstanceMethod<&Context2d::QuadraticCurveTo>("quadraticCurveTo", napi_default_method),
InstanceMethod<&Context2d::BeginPath>("beginPath", napi_default_method),
InstanceMethod<&Context2d::ClosePath>("closePath", napi_default_method),
InstanceMethod<&Context2d::Arc>("arc", napi_default_method),
InstanceMethod<&Context2d::ArcTo>("arcTo", napi_default_method),
InstanceMethod<&Context2d::Ellipse>("ellipse", napi_default_method),
InstanceMethod<&Context2d::SetLineDash>("setLineDash", napi_default_method),
InstanceMethod<&Context2d::GetLineDash>("getLineDash", napi_default_method),
InstanceMethod<&Context2d::CreatePattern>("createPattern", napi_default_method),
InstanceMethod<&Context2d::CreateLinearGradient>("createLinearGradient", napi_default_method),
InstanceMethod<&Context2d::CreateRadialGradient>("createRadialGradient", napi_default_method),
#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 16, 0)
InstanceMethod<&Context2d::BeginTag>("beginTag", napi_default_method),
InstanceMethod<&Context2d::EndTag>("endTag", napi_default_method),
#endif
InstanceAccessor<&Context2d::GetFormat>("pixelFormat", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetPatternQuality, &Context2d::SetPatternQuality>("patternQuality", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetImageSmoothingEnabled, &Context2d::SetImageSmoothingEnabled>("imageSmoothingEnabled", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetGlobalCompositeOperation, &Context2d::SetGlobalCompositeOperation>("globalCompositeOperation", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetGlobalAlpha, &Context2d::SetGlobalAlpha>("globalAlpha", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetShadowColor, &Context2d::SetShadowColor>("shadowColor", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetMiterLimit, &Context2d::SetMiterLimit>("miterLimit", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetLineWidth, &Context2d::SetLineWidth>("lineWidth", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetLineCap, &Context2d::SetLineCap>("lineCap", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetLineJoin, &Context2d::SetLineJoin>("lineJoin", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetLineDashOffset, &Context2d::SetLineDashOffset>("lineDashOffset", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetShadowOffsetX, &Context2d::SetShadowOffsetX>("shadowOffsetX", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetShadowOffsetY, &Context2d::SetShadowOffsetY>("shadowOffsetY", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetShadowBlur, &Context2d::SetShadowBlur>("shadowBlur", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetAntiAlias, &Context2d::SetAntiAlias>("antialias", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetTextDrawingMode, &Context2d::SetTextDrawingMode>("textDrawingMode", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetQuality, &Context2d::SetQuality>("quality", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetCurrentTransform, &Context2d::SetCurrentTransform>("currentTransform", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetFillStyle, &Context2d::SetFillStyle>("fillStyle", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetStrokeStyle, &Context2d::SetStrokeStyle>("strokeStyle", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetFont, &Context2d::SetFont>("font", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetTextBaseline, &Context2d::SetTextBaseline>("textBaseline", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetTextAlign, &Context2d::SetTextAlign>("textAlign", napi_default_jsproperty),
InstanceAccessor<&Context2d::GetDirection, &Context2d::SetDirection>("direction", napi_default_jsproperty)
});
exports.Set("CanvasRenderingContext2d", ctor);
data->Context2dCtor = Napi::Persistent(ctor);
}
/*
* Create a cairo context.
*/
Context2d::Context2d(const Napi::CallbackInfo& info) : Napi::ObjectWrap<Context2d>(info), env(info.Env()) {
InstanceData* data = env.GetInstanceData<InstanceData>();
if (!info[0].IsObject()) {
Napi::TypeError::New(env, "Canvas expected").ThrowAsJavaScriptException();
return;
}
Napi::Object obj = info[0].As<Napi::Object>();
if (!obj.InstanceOf(data->CanvasCtor.Value()).UnwrapOr(false)) {
if (!env.IsExceptionPending()) {
Napi::TypeError::New(env, "Canvas expected").ThrowAsJavaScriptException();
}
return;
}
_canvas = Canvas::Unwrap(obj);
bool isImageBackend = _canvas->backend()->getName() == "image";
if (isImageBackend) {
cairo_format_t format = ImageBackend::DEFAULT_FORMAT;
if (info[1].IsObject()) {
Napi::Object ctxAttributes = info[1].As<Napi::Object>();
Napi::Value pixelFormat;
if (ctxAttributes.Get("pixelFormat").UnwrapTo(&pixelFormat) && pixelFormat.IsString()) {
std::string utf8PixelFormat = pixelFormat.As<Napi::String>();
if (utf8PixelFormat == "RGBA32") format = CAIRO_FORMAT_ARGB32;
else if (utf8PixelFormat == "RGB24") format = CAIRO_FORMAT_RGB24;
else if (utf8PixelFormat == "A8") format = CAIRO_FORMAT_A8;
else if (utf8PixelFormat == "RGB16_565") format = CAIRO_FORMAT_RGB16_565;
else if (utf8PixelFormat == "A1") format = CAIRO_FORMAT_A1;
#ifdef CAIRO_FORMAT_RGB30
else if (utf8PixelFormat == "RGB30") format = CAIRO_FORMAT_RGB30;
#endif
}
// alpha: false forces use of RGB24
Napi::Value alpha;
if (ctxAttributes.Get("alpha").UnwrapTo(&alpha) && alpha.IsBoolean() && !alpha.As<Napi::Boolean>().Value()) {
format = CAIRO_FORMAT_RGB24;
}
}
static_cast<ImageBackend *>(_canvas->backend())->setFormat(format);
}
_context = _canvas->createCairoContext();
_layout = pango_cairo_create_layout(_context);
// As of January 2023, Pango rounds glyph positions which renders text wider
// or narrower than the browser. See #2184 for more information
#if PANGO_VERSION_CHECK(1, 44, 0)
pango_context_set_round_glyph_positions(pango_layout_get_context(_layout), FALSE);
#endif
pango_layout_set_auto_dir(_layout, FALSE);
states.emplace();
state = &states.top();
pango_layout_set_font_description(_layout, state->fontDescription);
}
/*
* Destroy cairo context.
*/
Context2d::~Context2d() {
if (_layout) g_object_unref(_layout);
if (_context) cairo_destroy(_context);
_resetPersistentHandles();
}
/*
* Reset canvas state.
*/
void Context2d::resetState() {
states.pop();
states.emplace();
pango_layout_set_font_description(_layout, state->fontDescription);
_resetPersistentHandles();
}
void Context2d::_resetPersistentHandles() {
_fillStyle.Reset();
_strokeStyle.Reset();
}
/*
* Save cairo / canvas state.
*/
void
Context2d::save() {
cairo_save(_context);
states.emplace(states.top());
state = &states.top();
}
/*
* Restore cairo / canvas state.
*/
void
Context2d::restore() {
if (states.size() > 1) {
cairo_restore(_context);
states.pop();
state = &states.top();
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 {
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) {
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(Napi::Value value) {
cairo_fill_rule_t rule = CAIRO_FILL_RULE_WINDING;
if (value.IsString()) {
std::string str = value.As<Napi::String>().Utf8Value();
if (str == "evenodd") {
rule = CAIRO_FILL_RULE_EVEN_ODD;
}
}
cairo_set_fill_rule(_context, rule);
}
void
Context2d::fill(bool preserve) {
cairo_pattern_t *new_pattern;
bool needsRestore = false;
if (state->fillPattern) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_pattern(state->fillPattern, state->globalAlpha);
if (new_pattern == NULL) {
Napi::Error::New(env, "Failed to initialize context").ThrowAsJavaScriptException();
// failed to allocate
return;
}
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_pattern_set_filter(state->fillPattern, state->patternQuality);
cairo_set_source(_context, state->fillPattern);
}
repeat_type_t repeat = Pattern::get_repeat_type_for_cairo_pattern(state->fillPattern);
if (repeat == NO_REPEAT) {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_NONE);
} else if (repeat == REPEAT) {
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_REPEAT);
} else {
cairo_save(_context);
cairo_path_t *savedPath = cairo_copy_path(_context);
cairo_surface_t *patternSurface = nullptr;
cairo_pattern_get_surface(cairo_get_source(_context), &patternSurface);
double width, height;
if (repeat == REPEAT_X) {
double x1, x2;
cairo_path_extents(_context, &x1, nullptr, &x2, nullptr);
width = x2 - x1;
height = cairo_image_surface_get_height(patternSurface);
} else {
double y1, y2;
cairo_path_extents(_context, nullptr, &y1, nullptr, &y2);
width = cairo_image_surface_get_width(patternSurface);
height = y2 - y1;
}
cairo_new_path(_context);
cairo_rectangle(_context, 0, 0, width, height);
cairo_clip(_context);
cairo_append_path(_context, savedPath);
cairo_path_destroy(savedPath);
cairo_pattern_set_extend(cairo_get_source(_context), CAIRO_EXTEND_REPEAT);
needsRestore = true;
}
} else if (state->fillGradient) {
if (state->globalAlpha < 1) {
new_pattern = create_transparent_gradient(state->fillGradient, state->globalAlpha);
if (new_pattern == NULL) {
Napi::Error::New(env, "Unexpected gradient type").ThrowAsJavaScriptException();
// failed to recognize gradient
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);
}
if (needsRestore) {
cairo_restore(_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) {
Napi::Error::New(env, "Failed to initialize context").ThrowAsJavaScriptException();
// failed to allocate
return;
}
cairo_set_source(_context, new_pattern);
cairo_pattern_destroy(new_pattern);
} else {
cairo_pattern_set_filter(state->strokePattern, state->patternQuality);
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) {
Napi::Error::New(env, "Unexpected gradient type").ThrowAsJavaScriptException();
// failed to recognize gradient
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);
// 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 );
const unsigned int size = width * height * sizeof(unsigned);
unsigned* precalc = (unsigned*)malloc(size);
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;
bool modified = false;
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;
if (!modified) modified = true;
pix += 4;
}
}
if (!modified) {
memset(precalc, 0, size);
}
// 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);
}
/*
* Get format (string).
*/
Napi::Value
Context2d::GetFormat(const Napi::CallbackInfo& info) {
std::string pixelFormatString;
switch (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 env.Null();
}
return Napi::String::New(env, pixelFormatString);
}
/*
* Create a new page.
*/
void
Context2d::AddPage(const Napi::CallbackInfo& info) {
if (canvas()->backend()->getName() != "pdf") {
Napi::Error::New(env, "only PDF canvases support .addPage()").ThrowAsJavaScriptException();
return;
}
cairo_show_page(context());
Napi::Number zero = Napi::Number::New(env, 0);
int width = info[0].ToNumber().UnwrapOr(zero).Int32Value();
int height = info[1].ToNumber().UnwrapOr(zero).Int32Value();
if (width < 1) width = canvas()->getWidth();
if (height < 1) height = canvas()->getHeight();
cairo_pdf_surface_set_size(canvas()->surface(), width, height);
}
/*
* Get text direction.
*/
Napi::Value
Context2d::GetDirection(const Napi::CallbackInfo& info) {
return Napi::String::New(env, state->direction);
}
/*
* Set text direction.
*/
void
Context2d::SetDirection(const Napi::CallbackInfo& info, const Napi::Value& value) {
if (!value.IsString()) return;
std::string dir = value.As<Napi::String>();
if (dir != "ltr" && dir != "rtl") return;
state->direction = dir;
}
/*
* Put image data.
*
* - imageData, dx, dy
* - imageData, dx, dy, sx, sy, sw, sh
*
*/
void
Context2d::PutImageData(const Napi::CallbackInfo& info) {
if (!info[0].IsObject()) {
Napi::TypeError::New(env, "ImageData expected").ThrowAsJavaScriptException();
return;
}
Napi::Object obj = info[0].As<Napi::Object>();
InstanceData* data = env.GetInstanceData<InstanceData>();
if (!obj.InstanceOf(data->ImageDataCtor.Value()).UnwrapOr(false)) {
if (!env.IsExceptionPending()) {
Napi::TypeError::New(env, "ImageData expected").ThrowAsJavaScriptException();
}
return;
}
ImageData *imageData = ImageData::Unwrap(obj);
Napi::Number zero = Napi::Number::New(env, 0);
uint8_t *src = imageData->data();
uint8_t *dst = canvas()->data();
int dstStride = canvas()->stride();
int Bpp = dstStride / canvas()->getWidth();
int srcStride = Bpp * imageData->width();
int sx = 0
, sy = 0
, sw = 0
, sh = 0
, dx = info[1].ToNumber().UnwrapOr(zero).Int32Value()
, dy = info[2].ToNumber().UnwrapOr(zero).Int32Value()
, 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 = info[3].ToNumber().UnwrapOr(zero).Int32Value();
sy = info[4].ToNumber().UnwrapOr(zero).Int32Value();
sw = info[5].ToNumber().UnwrapOr(zero).Int32Value();
sh = info[6].ToNumber().UnwrapOr(zero).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;
break;
default:
Napi::Error::New(env, "invalid arguments").ThrowAsJavaScriptException();
return;
}
// 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, canvas()->getWidth() - dx);
rows = (std::min)(sh, canvas()->getHeight() - dy);
if (cols <= 0 || rows <= 0) return;
switch (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?
Napi::Error::New(env, "putImageData for CANVAS_FORMAT_A1 is not yet implemented").ThrowAsJavaScriptException();
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
Napi::Error::New(env, "putImageData for CANVAS_FORMAT_RGB30 is not yet implemented").ThrowAsJavaScriptException();
break;
}
#endif
default: {
Napi::Error::New(env, "Invalid pixel format or not an image canvas").ThrowAsJavaScriptException();
return;
}
}
cairo_surface_mark_dirty_rectangle(
canvas()->surface()
, dx
, dy
, cols
, rows);
}
/*
* Get image data.
*
* - sx, sy, sw, sh
*
*/
Napi::Value
Context2d::GetImageData(const Napi::CallbackInfo& info) {
Napi::Number zero = Napi::Number::New(env, 0);
Canvas *canvas = this->canvas();