Add link tags for pdfs

CHANGELOG.md

@@ -9,6 +9,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ==================
 ### Changed
 ### Added
+* Support for links in PDFs
 ### Fixed
 
 

Readme.md

@@ -521,6 +521,15 @@ ctx.addPage(400, 800)
 ctx.fillText('Hello World 2', 50, 80)
 ```
 
+It is possible to add hyperlinks use `.beginTag(uri)` and `.closeTag()`:
+
+```js
+ctx.beginTag("https://google.com")
+ctx.font = '22px Helvetica'
+ctx.fillText('Hello World', 50, 80)
+ctx.closeTag()
+```
+
 See also:
 
 * [Image#dataMode](#imagedatamode) for embedding JPEGs in PDFs

examples/pdf-link.js

@@ -0,0 +1,19 @@
+const fs = require('fs')
+const Canvas = require('..')
+
+const canvas = Canvas.createCanvas(400, 200, 'pdf')
+const ctx = canvas.getContext('2d')
+
+let y = 80
+let x = 50
+
+ctx.beginTag("https://google.com")
+ctx.font = '22px Helvetica'
+ctx.fillText('node-canvas pdf', x, y)
+ctx.closeTag()
+
+fs.writeFile('out.pdf', canvas.toBuffer(), function (err) {
+ if (err) throw err
+
+ console.log('created out.pdf')
+})

src/CanvasRenderingContext2d.cc

@@ -134,6 +134,10 @@ Context2d::Initialize(Napi::Env& env, Napi::Object& exports) {
  InstanceMethod<&Context2d::CreatePattern>("createPattern"),
  InstanceMethod<&Context2d::CreateLinearGradient>("createLinearGradient"),
  InstanceMethod<&Context2d::CreateRadialGradient>("createRadialGradient"),
+ #if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 16, 0)
+ InstanceMethod<&Context2d::BeginTag>("beginTag", napi_default_method),
+ InstanceMethod<&Context2d::CloseTag>("closeTag", napi_default_method),
+ #endif
  InstanceAccessor<&Context2d::GetFormat>("pixelFormat"),
  InstanceAccessor<&Context2d::GetPatternQuality, &Context2d::SetPatternQuality>("patternQuality"),
  InstanceAccessor<&Context2d::GetImageSmoothingEnabled, &Context2d::SetImageSmoothingEnabled>("imageSmoothingEnabled"),
@@ -3354,3 +3358,29 @@ Context2d::Ellipse(const Napi::CallbackInfo& info) {
  }
  cairo_set_matrix(ctx, &save_matrix);
 }
+
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 16, 0)
+
+/*
+ * Open and close a link tag
+ */
+
+void
+Context2d::BeginTag(const Napi::CallbackInfo& info) {
+ Napi::String strValue;
+ if (!info[0].ToString().UnwrapTo(&strValue)) return;
+
+ std::string str = strValue.Utf8Value();
+ std::string uri = "uri='" + str + "'";
+
+ cairo_t *ctx = context();
+ cairo_tag_begin(ctx, CAIRO_TAG_LINK, uri.c_str());
+}
+
+void
+Context2d::CloseTag(const Napi::CallbackInfo& info) {
+ cairo_t *ctx = context();
+ cairo_tag_end(ctx, CAIRO_TAG_LINK);
+}
+
+#endif

src/CanvasRenderingContext2d.h

@@ -178,6 +178,10 @@ class Context2d : public Napi::ObjectWrap<Context2d> {
  void SetFont(const Napi::CallbackInfo& info, const Napi::Value& value);
  void SetTextBaseline(const Napi::CallbackInfo& info, const Napi::Value& value);
  void SetTextAlign(const Napi::CallbackInfo& info, const Napi::Value& value);
+ #if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 16, 0)
+ void BeginTag(const Napi::CallbackInfo& info);
+ void CloseTag(const Napi::CallbackInfo& info);
+ #endif
  inline void setContext(cairo_t *ctx) { _context = ctx; }
  inline cairo_t *context(){ return _context; }
  inline Canvas *canvas(){ return _canvas; }