RFR: 8238954: Improve performance of tiled snapshot rendering [v14]

[Kevin Rushforth]

On Wed, 1 Jul 2020 09:17:16 GMT, Frederic Thevenet <github.com+7450507+fthevenet at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/com/sun/javafx/tk/quantum/QuantumToolkit.java line 1638:
>> 
>>> 1637:                         renderWholeImage(x, y, w, h, rf, pImage);
>>> 1638:                     }
>>> 1639:                     params.platformImage = pImage;
>> 
>> I tried to write this code using for loop to make it little easy for reader to understand. This is just a suggestion, I
>> leave it to you to whether replace it or not,
>> int mTileWidth = computeTileSize(w, maxTextureSize);
>> int mTileHeight = computeTileSize(h, maxTextureSize);
>> IntBuffer buffer = IntBuffer.allocate(mTileWidth * mTileHeight);
>> 
>> int mTileXOffset = 0;
>> int mTileYOffset = 0;
>> for (mTileXOffset = 0; (mTileXOffset + mTileWidth) <= w; mTileXOffset += mTileWidth) {
>> 	for (mTileYOffset = 0; (mTileYOffset + mTileHeight) <= h; mTileYOffset += mTileHeight) {
>> 		renderTile(x, mTileXOffset, y, mTileYOffset, mTileWidth, mTileHeight,
>> 				buffer, rf, tileRttCache, pImage);
>> 	}
>> }
>> 
>> int rTileXOffset = mTileXOffset;
>> int rTileWidth = w - rTileXOffset;
>> if (rTileWidth > 0) {
>> 	for (int rTileYOffset = 0; (rTileYOffset + mTileHeight) <= h; rTileYOffset += mTileHeight) {
>> 		renderTile(x, rTileXOffset, y, rTileYOffset, rTileWidth, mTileHeight,
>> 				buffer, rf, tileRttCache, pImage);
>> 	}
>> }
>> 
>> int bTileYOffset = mTileYOffset;
>> int bTileHeight = h - bTileYOffset;
>> if (bTileHeight > 0) {
>> 	for (int bTileXOffset = 0; (bTileXOffset + mTileWidth) <= w; bTileXOffset += mTileWidth) {
>> 		renderTile(x, bTileXOffset, y, bTileYOffset, mTileWidth, bTileHeight,
>> 				buffer, rf, tileRttCache, pImage);
>> 	}
>> }
>> 
>> if (rTileWidth > 0 &&  bTileHeight > 0) {
>> 	renderTile(x, rTileXOffset, y, bTileYOffset, rTileWidth, bTileHeight,
>> 			buffer, rf, tileRttCache, pImage);
>> }
>
> Thanks for you suggestion.
> 
> The original code is still too fresh in my mind for me to really be able to say which version is easier to understand,
> so I'll let others with a fresh pair of eyes be the judge of that. However I think your code is arguably more concise -
> and overall more elegant - so I'd be happy to swap my version for yours, provided it is considered at least as readable
> as the original. WDYT?

We'll leave it up to you, but I note that it will require retesting if you adopt the suggested change.

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PR: https://git.openjdk.java.net/jfx/pull/112