Fix drawImage regression with particular use case of 9 arguments. (#1251)

* ok!

* ok!

* added-test

* fix lint

* reworked a name

Author: asturur

src/CanvasRenderingContext2d.cc

@@ -1112,8 +1112,8 @@ NAN_METHOD(Context2d::DrawImage) {
     , dy = 0
     , dw = 0
     , dh = 0
-    , fw = 0
-    , fh = 0;
+    , source_w = 0
+    , source_h = 0;
 
   cairo_surface_t *surface;
 
@@ -1125,15 +1125,15 @@ NAN_METHOD(Context2d::DrawImage) {
     if (!img->isComplete()) {
       return Nan::ThrowError("Image given has not completed loading");
     }
-    fw = sw = img->width;
-    fh = sh = img->height;
+    source_w = sw = img->width;
+    source_h = sh = img->height;
     surface = img->surface();
 
   // Canvas
   } else if (Nan::New(Canvas::constructor)->HasInstance(obj)) {
     Canvas *canvas = Nan::ObjectWrap::Unwrap<Canvas>(obj);
-    fw = sw = canvas->getWidth();
-    fh = sh = canvas->getHeight();
+    source_w = sw = canvas->getWidth();
+    source_h = sh = canvas->getHeight();
     surface = canvas->surface();
 
   // Invalid
@@ -1183,17 +1183,30 @@ NAN_METHOD(Context2d::DrawImage) {
   float fx = (float) dw / sw;
   float fy = (float) dh / sh;
   bool needScale = dw != sw || dh != sh;
-  bool needCut = sw != fw || sh != fh;
+  bool needCut = sw != source_w || sh != source_h || sx < 0 || sy < 0;
+  bool needCairoClip = sx < 0 || sy < 0 || sw > source_w || sh > source_h;
 
   bool sameCanvas = surface == context->canvas()->surface();
-  bool needsExtraSurface = sameCanvas || needCut || needScale;
+  bool needsExtraSurface = sameCanvas || needCut || needScale || needCairoClip;
   cairo_surface_t *surfTemp = NULL;
   cairo_t *ctxTemp = NULL;
 
   if (needsExtraSurface) {
     surfTemp = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, dw, dh);
     ctxTemp = cairo_create(surfTemp);
     cairo_scale(ctxTemp, fx, fy);
+    if (needCairoClip) {
+      float clip_w = (std::min)(sw, source_w);
+      float clip_h = (std::min)(sh, source_h);
+      if (sx > 0) {
+        clip_w -= sx;
+      }
+      if (sy > 0) {
+        clip_h -= sy;
+      }
+      cairo_rectangle(ctxTemp, -sx , -sy , clip_w, clip_h);
+      cairo_clip(ctxTemp);
+    }
     cairo_set_source_surface(ctxTemp, surface, -sx, -sy);
     cairo_pattern_set_filter(cairo_get_source(ctxTemp), context->state->imageSmoothingEnabled ? context->state->patternQuality : CAIRO_FILTER_NEAREST);
     cairo_pattern_set_extend(cairo_get_source(ctxTemp), CAIRO_EXTEND_REFLECT);

test/public/tests.js

@@ -1239,6 +1239,7 @@ gco.forEach(op => {
     var img2 = new Image()
     img1.onload = function () {
       img2.onload = function () {
+        ctx.globalAlpha = 0.7
         ctx.drawImage(img1, 0, 0)
         ctx.globalCompositeOperation = op
         ctx.drawImage(img2, 0, 0)
@@ -1250,6 +1251,42 @@ gco.forEach(op => {
   }
 })
 
+gco.forEach(op => {
+  tests['9 args, transform, globalCompositeOperator ' + op] = function (ctx, done) {
+    var img1 = new Image()
+    var img2 = new Image()
+    img1.onload = function () {
+      img2.onload = function () {
+        ctx.globalAlpha = 0.7
+        ctx.drawImage(img1, 0, 0)
+        ctx.globalCompositeOperation = op
+        ctx.rotate(0.1)
+        ctx.scale(0.8, 1.2)
+        ctx.translate(5, -5)
+        ctx.drawImage(img2, -80, -50, 400, 400, 10, 10, 180, 180)
+        done()
+      }
+      img2.src = imageSrc('newcontent.png')
+    }
+    img1.src = imageSrc('existing.png')
+  }
+})
+
+tests['drawImage issue #1249'] = function (ctx, done) {
+  var img1 = new Image()
+  var img2 = new Image()
+  img1.onload = function () {
+    img2.onload = function () {
+      ctx.drawImage(img1, 0, 0, 200, 200)
+      ctx.drawImage(img2, -8, -8, 18, 18, 0, 0, 200, 200)
+      ctx.restore()
+      done()
+    }
+    img2.src = imageSrc('checkers.png')
+  }
+  img1.src = imageSrc('chrome.jpg')
+}
+
 tests['known bug #416'] = function (ctx, done) {
   var img1 = new Image()
   var img2 = new Image()