Bug 35349 – IFrame background rendered white until loading of src url

• Component: Layout and Rendering
• Status: UNCONFIRMED

[Mihnea Ovidenie]

Hi,

I use the following HTML:

<div style="float: left; background-color: rgb(0, 255, 0); width: 320px; height: 240px;">
    <iframe id="frame1" style="width:200px; height: 200px;" src="http://www.adobe.com/devnet">
    </iframe>
</div>

After Safari 4 beta, more exactly after changes from: http://trac.webkit.org/changeset/43646, the background of the frame is rendered as white until the site is loaded.
The problem appears from the following line from RenderBoxModelObject.cpp function paintFillLayerExtended:
...
HTMLElement* body = document()->body();
if (body) {
    // Can't scroll a frameset document anyway.
    isOpaqueRoot = body->hasLocalName(framesetTag);
}
... 

Before loading the document in the iframe, the body of the document is null and therefore the frame is considered opaque. Before this change, in changeset 42348, there was a check for transparency in the same function:
isTransparent = !body || !body->hasLocalName(framesetTag);

If the current code is changed to take into account that the body can be null:
HTMLElement* body = document()->body();
if (body) {
    // Can't scroll a frameset document anyway.
    isOpaqueRoot = body && body->hasLocalName(framesetTag);
}
then the iframe is considered to be transparent and the white background is gone.

The problem can be seen on latest WebKit, Safari 4.0.4, Chrome on both Win/Mac.
FF3.5.7 does not have the problem.

I tend to say this is a bug but please feel free to correct me if i am wrong and the normal behavior should be like it is now.

Regards,
Mihnea Ovidenie