Merge pull request #165 from c-spencer/master

Add textDrawingMode context2d property for controlling whether to use paths or glyphs.

Readme.md

@@ -132,6 +132,14 @@ Given one of the values below will alter pattern (gradients, images, etc) render
   - good
   - best
 
+### CanvasRenderingContext2d#textDrawingMode
+
+Can be either `path` or `glyph`. Using `glyph` is much faster than `path` for drawing, and when using a PDF context will embed the text natively, so will be selectable and lower filesize. The downside is that cairo does not have any subpixel precision for `glyph`, so this will be noticeably lower quality for text positioning in cases such as rotated text. Also, strokeText in `glyph` will act the same as fillText, except using the stroke style for the fill.
+
+Defaults to _path_.
+
+This property is tracked as part of the canvas state in save/restore.
+
 ### Global Composite Operations
 
 In addition to those specified and commonly implemented by browsers, the following have been added:

src/CanvasRenderingContext2d.cc

@@ -110,6 +110,7 @@ Context2d::Initialize(Handle<Object> target) {
   proto->SetAccessor(String::NewSymbol("shadowOffsetY"), GetShadowOffsetY, SetShadowOffsetY);
   proto->SetAccessor(String::NewSymbol("shadowBlur"), GetShadowBlur, SetShadowBlur);
   proto->SetAccessor(String::NewSymbol("antialias"), GetAntiAlias, SetAntiAlias);
+  proto->SetAccessor(String::NewSymbol("textDrawingMode"), GetTextDrawingMode, SetTextDrawingMode);
   target->Set(String::NewSymbol("CanvasRenderingContext2d"), constructor->GetFunction());
 }
 
@@ -135,6 +136,7 @@ Context2d::Context2d(Canvas *canvas) {
   state->stroke = transparent;
   state->shadow = transparent_black;
   state->patternQuality = CAIRO_FILTER_GOOD;
+  state->textDrawingMode = TEXT_DRAW_PATHS;
 }
 
 /*
@@ -932,6 +934,38 @@ Context2d::SetAntiAlias(Local<String> prop, Local<Value> val, const AccessorInfo
   cairo_set_antialias(ctx, a);
 }
 
+/*
+ * Get text drawing mode.
+ */
+
+Handle<Value>
+Context2d::GetTextDrawingMode(Local<String> prop, const AccessorInfo &info) {
+  HandleScope scope;
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(info.This());
+  const char *mode;
+  if (context->state->textDrawingMode == TEXT_DRAW_PATHS) {
+    mode = "path";
+  } else if (context->state->textDrawingMode == TEXT_DRAW_GLYPHS) {
+    mode = "glyph";
+  }
+  return scope.Close(String::NewSymbol(mode));
+}
+
+/*
+ * Set text drawing mode.
+ */
+
+void
+Context2d::SetTextDrawingMode(Local<String> prop, Local<Value> val, const AccessorInfo &info) {
+  String::AsciiValue str(val->ToString());
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(info.This());
+  if (0 == strcmp("path", *str)) {
+    context->state->textDrawingMode = TEXT_DRAW_PATHS;
+  } else if (0 == strcmp("glyph", *str)) {
+    context->state->textDrawingMode = TEXT_DRAW_GLYPHS;
+  }
+}
+
 /*
  * Get miter limit.
  */
@@ -1448,8 +1482,13 @@ Context2d::FillText(const Arguments &args) {
   Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
 
   context->savePath();
-  context->setTextPath(*str, x, y);
-  context->fill();
+  if (context->state->textDrawingMode == TEXT_DRAW_GLYPHS) {
+    context->fill();
+    context->setTextPath(*str, x, y);
+  } else if (context->state->textDrawingMode == TEXT_DRAW_PATHS) {
+    context->setTextPath(*str, x, y);
+    context->fill();
+  }
   context->restorePath();
 
   return Undefined();
@@ -1473,8 +1512,13 @@ Context2d::StrokeText(const Arguments &args) {
   Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
 
   context->savePath();
-  context->setTextPath(*str, x, y);
-  context->stroke();
+  if (context->state->textDrawingMode == TEXT_DRAW_GLYPHS) {
+    context->stroke();
+    context->setTextPath(*str, x, y);
+  } else if (context->state->textDrawingMode == TEXT_DRAW_PATHS) {
+    context->setTextPath(*str, x, y);
+    context->stroke();
+  }
   context->restorePath();
 
   return Undefined();
@@ -1529,7 +1573,11 @@ Context2d::setTextPath(const char *str, double x, double y) {
   }
 
   cairo_move_to(_context, x, y);
-  cairo_text_path(_context, str);
+  if (state->textDrawingMode == TEXT_DRAW_PATHS) {
+    cairo_text_path(_context, str);
+  } else if (state->textDrawingMode == TEXT_DRAW_GLYPHS) {
+    cairo_show_text(_context, str);
+  }
 }
 
 /*

src/CanvasRenderingContext2d.h

@@ -12,6 +12,11 @@
 #include "Canvas.h"
 #include "CanvasGradient.h"
 
+typedef enum {
+  TEXT_DRAW_PATHS,
+  TEXT_DRAW_GLYPHS
+} canvas_draw_mode_t;
+
 /*
  * State struct.
  *
@@ -34,6 +39,7 @@ typedef struct {
   int shadowBlur;
   double shadowOffsetX;
   double shadowOffsetY;
+  canvas_draw_mode_t textDrawingMode;
 } canvas_state_t;
 
 class Context2d: public node::ObjectWrap {
@@ -95,6 +101,7 @@ class Context2d: public node::ObjectWrap {
     static Handle<Value> GetShadowOffsetY(Local<String> prop, const AccessorInfo &info);
     static Handle<Value> GetShadowBlur(Local<String> prop, const AccessorInfo &info);
     static Handle<Value> GetAntiAlias(Local<String> prop, const AccessorInfo &info);
+    static Handle<Value> GetTextDrawingMode(Local<String> prop, const AccessorInfo &info);
     static void SetPatternQuality(Local<String> prop, Local<Value> val, const AccessorInfo &info);
     static void SetGlobalCompositeOperation(Local<String> prop, Local<Value> val, const AccessorInfo &info);
     static void SetGlobalAlpha(Local<String> prop, Local<Value> val, const AccessorInfo &info);
@@ -107,6 +114,7 @@ class Context2d: public node::ObjectWrap {
     static void SetShadowOffsetY(Local<String> prop, Local<Value> val, const AccessorInfo &info);
     static void SetShadowBlur(Local<String> prop, Local<Value> val, const AccessorInfo &info);
     static void SetAntiAlias(Local<String> prop, Local<Value> val, const AccessorInfo &info);
+    static void SetTextDrawingMode(Local<String> prop, Local<Value> val, const AccessorInfo &info);
     inline void setContext(cairo_t *ctx) { _context = ctx; }
     inline cairo_t *context(){ return _context; }
     inline Canvas *canvas(){ return _canvas; }