Render small-caps font variant

CHANGELOG.md

@@ -20,6 +20,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 * Fix compile errors with cairo
 * Fix Image#complete if the image failed to load.
 * Upgrade node-pre-gyp to v0.15.0 to use latest version of needle to fix error when downloading prebuilds.
+* The small-caps variant setting is now honored if included in a font string
 
 2.6.1
 ==================

index.js

@@ -81,6 +81,8 @@ module.exports = {
   gifVersion: bindings.gifVersion ? bindings.gifVersion.replace(/[^.\d]/g, '') : undefined,
   /** freetype version. */
   freetypeVersion: bindings.freetypeVersion,
+  /** pango version. */
+  pangoVersion: bindings.pangoVersion,
   /** rsvg version. */
   rsvgVersion: bindings.rsvgVersion
 }

package.json

@@ -59,6 +59,7 @@
     "express": "^4.16.3",
     "mocha": "^5.2.0",
     "pixelmatch": "^4.0.2",
+    "semver": "^7.3.2",
     "standard": "^12.0.1"
   },
   "engines": {

src/CanvasRenderingContext2d.cc

@@ -199,6 +199,7 @@ Context2d::Context2d(Canvas *canvas) {
 Context2d::~Context2d() {
   while(stateno >= 0) {
     pango_font_description_free(states[stateno]->fontDescription);
+    pango_attr_list_unref(states[stateno]->textAttributes);
     free(states[stateno--]);
   }
   g_object_unref(_layout);
@@ -213,6 +214,7 @@ Context2d::~Context2d() {
 void Context2d::resetState(bool init) {
   if (!init) {
     pango_font_description_free(state->fontDescription);
+    pango_attr_list_unref(states[stateno]->textAttributes);
   }
 
   state->shadowBlur = 0;
@@ -235,6 +237,8 @@ void Context2d::resetState(bool init) {
   state->fontDescription = pango_font_description_from_string("sans serif");
   pango_font_description_set_absolute_size(state->fontDescription, 10 * PANGO_SCALE);
   pango_layout_set_font_description(_layout, state->fontDescription);
+  state->textAttributes = pango_attr_list_new();
+  pango_layout_set_attributes(_layout, state->textAttributes);
 
   _resetPersistentHandles();
 }
@@ -258,6 +262,8 @@ Context2d::save() {
     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);
+    states[stateno]->textAttributes = pango_attr_list_copy(states[stateno-1]->textAttributes);
+    pango_layout_set_attributes(_layout, states[stateno]->textAttributes);
     state = states[stateno];
   }
 }
@@ -271,10 +277,12 @@ Context2d::restore() {
   if (stateno > 0) {
     cairo_restore(_context);
     pango_font_description_free(states[stateno]->fontDescription);
+    pango_attr_list_unref(states[stateno]->textAttributes);
     free(states[stateno]);
     states[stateno] = NULL;
     state = states[--stateno];
     pango_layout_set_font_description(_layout, state->fontDescription);
+    pango_layout_set_attributes(_layout, state->textAttributes);
   }
 }
 
@@ -2499,6 +2507,7 @@ NAN_GETTER(Context2d::GetFont) {
 
 /*
  * Set font:
+ *   - variant
  *   - weight
  *   - style
  *   - size
@@ -2523,6 +2532,7 @@ NAN_SETTER(Context2d::SetFont) {
   if (mparsed->IsUndefined()) return;
   Local<Object> font = Nan::To<Object>(mparsed).ToLocalChecked();
 
+  Nan::Utf8String variant(Nan::Get(font, Nan::New("variant").ToLocalChecked()).ToLocalChecked());
   Nan::Utf8String weight(Nan::Get(font, Nan::New("weight").ToLocalChecked()).ToLocalChecked());
   Nan::Utf8String style(Nan::Get(font, Nan::New("style").ToLocalChecked()).ToLocalChecked());
   double size = Nan::To<double>(Nan::Get(font, Nan::New("size").ToLocalChecked()).ToLocalChecked()).FromMaybe(0);
@@ -2547,6 +2557,16 @@ NAN_SETTER(Context2d::SetFont) {
   context->state->fontDescription = sys_desc;
   pango_layout_set_font_description(context->_layout, sys_desc);
 
+  #if PANGO_VERSION >= PANGO_VERSION_ENCODE(1, 37, 1)
+  PangoAttribute *features;
+  if (strlen(*variant) > 0 && strcmp("small-caps", *variant) == 0) {
+    features = pango_attr_font_features_new("smcp 1, onum 1");
+  } else {
+    features = pango_attr_font_features_new("");
+  }
+  pango_attr_list_change(context->state->textAttributes, features);
+  #endif
+
   context->_font.Reset(value);
 }
 

src/CanvasRenderingContext2d.h

@@ -37,6 +37,7 @@ typedef struct {
   double shadowOffsetY;
   canvas_draw_mode_t textDrawingMode;
   PangoFontDescription *fontDescription;
+  PangoAttrList *textAttributes;
   bool imageSmoothingEnabled;
 } canvas_state_t;
 

src/init.cc

@@ -87,6 +87,10 @@ NAN_MODULE_INIT(init) {
   char freetype_version[10];
   snprintf(freetype_version, 10, "%d.%d.%d", FREETYPE_MAJOR, FREETYPE_MINOR, FREETYPE_PATCH);
   Nan::Set(target, Nan::New<String>("freetypeVersion").ToLocalChecked(), Nan::New<String>(freetype_version).ToLocalChecked()).Check();
+
+  char pango_version[10];
+  snprintf(pango_version, 10, "%d.%d.%d", PANGO_VERSION_MAJOR, PANGO_VERSION_MINOR, PANGO_VERSION_MICRO);
+  Nan::Set(target, Nan::New<String>("pangoVersion").ToLocalChecked(), Nan::New<String>(pango_version).ToLocalChecked()).Check();
 }
 
 NODE_MODULE(canvas, init);

test/canvas.test.js

@@ -11,10 +11,12 @@ const createImageData = require('../').createImageData
 const loadImage = require('../').loadImage
 const parseFont = require('../').parseFont
 const registerFont = require('../').registerFont
+const pangoVersion = require('../').pangoVersion
 
 const assert = require('assert')
 const os = require('os')
 const Readable = require('stream').Readable
+const semver = require('semver')
 
 describe('Canvas', function () {
   // Run with --expose-gc and uncomment this line to help find memory problems:
@@ -446,6 +448,38 @@ describe('Canvas', function () {
     assert.equal(ctx.font, '15px Arial, sans-serif')
   });
 
+  it('Context2d#font=small-caps', function () {
+    if (!semver.satisfies(pangoVersion, '>=1.37.1')){
+      this.skip();
+    }
+
+    registerFont('./examples/crimsonFont/Crimson-Bold.ttf', {family: 'Crimson'})
+    let canvas = createCanvas(200, 200),
+        ctx = canvas.getContext('2d');
+
+    // here is where the dot will appear above a lower-case 'i' (and be missing for small-caps)
+    let offsetX = 15, offsetY = -115;
+
+    ctx.font = "180px Crimson";
+    ctx.fillText('i', 20, 180);
+    let lcDottedI = ctx.getImageData(20 + offsetX, 180 + offsetY, 20, 20).data;
+    assert.equal(lcDottedI.some(p => p > 0), true);
+
+    ctx.save()
+
+    ctx.font = "small-caps 180px Crimson";
+    ctx.fillText('i', 80, 180);
+    let scEmptySpace = ctx.getImageData(80 + offsetX, 180 + offsetY, 20, 20).data;
+    assert.equal(scEmptySpace.every(p => p == 0), true);
+
+    ctx.restore()
+
+    ctx.fillText('i', 140, 180);
+    let lcDottedAgain = ctx.getImageData(140 + offsetX, 180 + offsetY, 20, 20).data;
+    assert.equal(lcDottedAgain.some(p => p > 0), true);
+  });
+
+
   it('Context2d#lineWidth=', function () {
     var canvas = createCanvas(200, 200)
       , ctx = canvas.getContext('2d');