On Tue, 1 May 2018, Ryan Joseph wrote:
On May 1, 2018, at 8:28 PM, Michael Van Canneyt <[email protected]> wrote:
Check the canvas demo (demo/rtl/democanvas2d.pas)
something like this?
var
canvas: TJSElement; // What type should this be?
gl: TJSWebGLRenderingContext;
begin
canvas := document.createElement('canvas');
document.body.appendChild(canvas);
gl := canvas.getContext('webgl');
You must do
gl := TJSWebGLRenderingContext(canvas.getContext('webgl'));
because getContext can return various classes depending on the argument.
canvas.width := newWidth;
canvas.height := newHeight;
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
Not sure about the type which createElement returns that has the getContext
method.
createElement returns guaranteed TJSElement, but normally it will be
TJSHTMLCanvasElement
for your call.
So
canvas: TJSHTMLCanvasElement;
begin
canvas:=TJSHTMLCanvasElement(document.createElement('canvas'));
Do you need document.body.appendChild also? Sorry it’s been a long time since I
used JS to do even simple things. Never knew it well.
Yes, you need that too to insert the new element in the DOM tree.
Michael.
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