Integrated: 8337681: PNGImageWriter uses much more memory than necessary

[Daniel Gredler]

On Thu, 1 Aug 2024 19:06:57 GMT, Daniel Gredler <duke at openjdk.org> wrote:

> At some point the `JPEGImageWriter` was optimized to reduce duplication / copying of rasters and data buffers (see `JDK-6266748`). However, `PNGImageWriter` never received a similar optimization, and is making unnecessary copies of raster and data buffers whenever PNG images are written.
> 
> Measurements: In a local test, `PNGImageWriter.write( )` and callees were initially showing up as an allocation hotspot (~400k objects / ~65 MB allocated), but after these optimizations I'm seeing much better numbers (~400 objects / ~740 KB allocated).

This pull request has now been integrated.

Changeset: 89a15f14
Author:    Daniel Gredler <daniel.gredler at gmail.com>
Committer: Laurent Bourgès <lbourges at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/89a15f1414f89d2dd32eac791e9155fcb4207e56
Stats:     200 lines in 2 files changed: 195 ins; 1 del; 4 mod

8337681: PNGImageWriter uses much more memory than necessary

Reviewed-by: prr, lbourges

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PR: https://git.openjdk.org/jdk/pull/20432