Auto merge of #21850 - servo:webgl, r=jdm

Don't use an intermediate PNG buffer in HTMLCanvasElement::ToDataURL

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1 files changed, 18 insertions, 22 deletions

diff --git a/components/script/dom/htmlcanvaselement.rs b/components/script/dom/htmlcanvaselement.rs
index 00b04db7ee8..09114a95d0a 100644
--- a/components/script/dom/htmlcanvaselement.rs
+++ b/components/script/dom/htmlcanvaselement.rs
@@ -98,8 +98,8 @@ impl HTMLCanvasElement {
         }
     }
 
-    pub fn get_size(&self) -> Size2D<i32> {
-        Size2D::new(self.Width() as i32, self.Height() as i32)
+    pub fn get_size(&self) -> Size2D<u32> {
+        Size2D::new(self.Width(), self.Height())
     }
 
     pub fn origin_is_clean(&self) -> bool {
@@ -277,7 +277,7 @@ impl HTMLCanvasElement {
         self.Height() != 0 && self.Width() != 0
     }
 
-    pub fn fetch_all_data(&self) -> Option<(Vec<u8>, Size2D<i32>)> {
+    pub fn fetch_all_data(&self) -> Option<(Vec<u8>, Size2D<u32>)> {
         let size = self.get_size();
 
         if size.width == 0 || size.height == 0 {
@@ -383,12 +383,11 @@ impl HTMLCanvasElementMethods for HTMLCanvasElement {
                     None => return Ok(USVString("data:,".into())),
                 }
             },
-            Some(CanvasContext::WebGL2(ref context)) => match context
-                .base_context()
-                .get_image_data(self.Width(), self.Height())
-            {
-                Some(data) => data,
-                None => return Ok(USVString("data:,".into())),
+            Some(CanvasContext::WebGL2(ref context)) => {
+                match context.base_context().get_image_data(self.Width(), self.Height()) {
+                    Some(data) => data,
+                    None => return Ok(USVString("data:,".into())),
+                }
             },
             None => {
                 // Each pixel is fully-transparent black.
@@ -396,19 +395,16 @@ impl HTMLCanvasElementMethods for HTMLCanvasElement {
             },
         };
 
-        // Only handle image/png for now.
-        let mime_type = "image/png";
-
-        let mut encoded = Vec::new();
-        {
-            let encoder: PNGEncoder<&mut Vec<u8>> = PNGEncoder::new(&mut encoded);
-            encoder
-                .encode(&raw_data, self.Width(), self.Height(), ColorType::RGBA(8))
-                .unwrap();
-        }
-
-        let encoded = base64::encode(&encoded);
-        Ok(USVString(format!("data:{};base64,{}", mime_type, encoded)))
+        // FIXME: Only handle image/png for now.
+        let mut png = Vec::new();
+        PNGEncoder::new(&mut png)
+            .encode(&raw_data, self.Width(), self.Height(), ColorType::RGBA(8))
+            .unwrap();
+        let mut url = "data:image/png;base64,".to_owned();
+        // FIXME(nox): Should this use base64::URL_SAFE?
+        // FIXME(nox): https://github.com/alicemaz/rust-base64/pull/56
+        base64::encode_config_buf(&png, base64::STANDARD, &mut url);
+        Ok(USVString(url))
     }
 }