Implement HTMLCanvasElement#toDataURL

This commit is contained in:
David Zbarsky 2015-10-25 15:20:34 -07:00
parent e49c7a3acb
commit a63c98c24a
31 changed files with 49 additions and 131 deletions

View file

@ -5,13 +5,16 @@
use canvas_traits::{CanvasMsg, FromLayoutMsg};
use dom::attr::Attr;
use dom::bindings::cell::DOMRefCell;
use dom::bindings::codegen::Bindings::CanvasRenderingContext2DBinding::CanvasRenderingContext2DMethods;
use dom::bindings::codegen::Bindings::HTMLCanvasElementBinding;
use dom::bindings::codegen::Bindings::HTMLCanvasElementBinding::HTMLCanvasElementMethods;
use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLContextAttributes;
use dom::bindings::codegen::UnionTypes::CanvasRenderingContext2DOrWebGLRenderingContext;
use dom::bindings::conversions::Castable;
use dom::bindings::error::{Error, Fallible};
use dom::bindings::global::GlobalRef;
use dom::bindings::js::{HeapGCValue, JS, LayoutJS, Root};
use dom::bindings::num::Finite;
use dom::bindings::utils::{Reflectable};
use dom::canvasrenderingcontext2d::{CanvasRenderingContext2D, LayoutCanvasRenderingContext2DHelpers};
use dom::document::Document;
@ -21,9 +24,12 @@ use dom::node::{Node, window_from_node};
use dom::virtualmethods::VirtualMethods;
use dom::webglrenderingcontext::{LayoutCanvasWebGLRenderingContextHelpers, WebGLRenderingContext};
use euclid::size::Size2D;
use image::ColorType;
use image::png::PNGEncoder;
use ipc_channel::ipc::{self, IpcSender};
use js::jsapi::{HandleValue, JSContext};
use offscreen_gl_context::GLContextAttributes;
use rustc_serialize::base64::{STANDARD, ToBase64};
use std::cell::Cell;
use std::iter::repeat;
use util::str::{DOMString, parse_unsigned_integer};
@ -246,6 +252,44 @@ impl HTMLCanvasElementMethods for HTMLCanvasElement {
_ => None
}
}
// https://html.spec.whatwg.org/multipage/#dom-canvas-todataurl
fn ToDataURL(&self,
_context: *mut JSContext,
_mime_type: Option<DOMString>,
_arguments: Vec<HandleValue>) -> Fallible<DOMString> {
// Step 1: Check the origin-clean flag (should be set in fillText/strokeText
// and currently unimplemented)
// Step 2.
if self.Width() == 0 || self.Height() == 0 {
return Ok("data:,".to_owned());
}
// Step 3.
if let Some(CanvasContext::Context2d(ref context)) = *self.context.borrow() {
let window = window_from_node(self);
let image_data = try!(context.GetImageData(Finite::wrap(0f64), Finite::wrap(0f64),
Finite::wrap(self.Width() as f64),
Finite::wrap(self.Height() as f64)));
let raw_data = image_data.get_data_array(&GlobalRef::Window(window.r()));
// 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 = encoded.to_base64(STANDARD);
Ok(format!("data:{};base64,{}", mime_type, encoded))
} else {
Err(Error::NotSupported)
}
}
}
impl VirtualMethods for HTMLCanvasElement {