1233605 - Cull some uses of gfxContext

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Nicholas Nethercote [inactive]]

Simple stuff.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: Cull some uses of gfxContext

Comment 2

[Daniel Holbert [:dholbert]]

Comment on attachment 8699768 [details] [diff] [review]
Cull some uses of gfxContext

Review of attachment 8699768 [details] [diff] [review]:
-----------------------------------------------------------------

[Looks like this is a no-op change; just pushing some DrawTarget lookups that are already happening to happen at more logical points, to reduce gfxContext usage. Cool.]

Just one nit:

::: gfx/thebes/gfxFont.cpp
@@ +1798,5 @@
>          }
>      }
>  
>      if (fontParams.haveColorGlyphs &&
> +        RenderColorGlyph(runParams.context->GetDrawTarget(),

[tl;dr: use runParams.dt here.]

Technically, this looks correct (in that you're just pushing the context->GetDrawTarget() lookup up one stack-level).

*But*:  runParams.context->GetDrawTarget() is probably overly-verbose, because runParams has an explicit ".dt" member (which is a reference to a DrawTarget), and we use that elsewhere in this file:
 https://mxr.mozilla.org/mozilla-central/search?string=arams.dt&find=gfxFont.cpp

And it looks like it's set up to be the same value you're using here (context->GetDrawTarget()), at least in the TextRunDrawParams that are instantiated in gfxTextRun.cpp (the only ones I found in some quick looking).

So I'm 99% sure you can assume .dt is equivalent to what you're using, and shorter & better (because it removes another gfxContext usage, hooray).

::: layout/base/FrameLayerBuilder.cpp
@@ +5728,5 @@
>   * items separately for each rect in the visible region rather
>   * than clipping to a complex region.
>   */
> +static bool
> +ShouldDrawRectsSeparately(DrawTarget& aDrawTarget, DrawRegionClip aClip)

<tangent>
I'm uncomfortable passing around C++ references to refcounted objects, for reasons discussed in bug 1230056 comment 3. But I guess the caller already has a "DrawTarget&" in this case, so it's semi-natural for this helper-function to take that as well.  Maybe this is more common than I thought, and I should relax my uneasiness? not sure.
</tangent>

In any case, this seems fine given that you're just using what the calling code already has.)

Comment 3

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #2)
> <tangent>
> I'm uncomfortable passing around C++ references to refcounted objects, for
> reasons discussed in bug 1230056 comment 3.

Sorry, wrong comment-number -- I meant to say "bug 1230056 comment 6" here.

Comment 4

[Nicholas Nethercote [inactive]]

Thank you for the fast review.

> [Looks like this is a no-op change; just pushing some DrawTarget lookups
> that are already happening to happen at more logical points, to reduce
> gfxContext usage. Cool.]

Correct. 


> [tl;dr: use runParams.dt here.]

Ah yes. I previously considered removing rumParams.dt and using runParams.context.GetDrawTarget() throughout to make things clearer but didn't because it made things more verbose.


> <tangent>
> I'm uncomfortable passing around C++ references to refcounted objects, for
> reasons discussed in bug 1230056 comment 3. But I guess the caller already
> has a "DrawTarget&" in this case, so it's semi-natural for this
> helper-function to take that as well.  Maybe this is more common than I
> thought, and I should relax my uneasiness? not sure.
> </tangent>
> 
> In any case, this seems fine given that you're just using what the calling
> code already has.)

We do have plenty of gfxContext& and DrawTarget& parameters in the code, but it's a reasonable objection and I've mostly been using DrawTarget* in other code I've converted, so I'll do likewise here.

Comment 5

[Nicholas Nethercote [inactive]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/41a7345c2c4aa3b2a4dbf7b5a6b65fc28027d523
Bug 1233605 - Cull some uses of gfxContext. r=dholbert.

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/41a7345c2c4a