|author||Milian Wolff <firstname.lastname@example.org>||2012-09-03 18:06:17 +0200|
|committer||Qt by Nokia <email@example.com>||2012-09-05 03:02:59 +0200|
Optimize QTextLayout/QTextEngine usage outside of QTextDocument.
When QTextLayout is used in a QTextDocument, many code paths use special caches and thus greatly outperform the raw QTextLayout version that operates directly on a QString. This patch brings some of these optimizations also to the raw version. We now also use a QFormatCollection in such cases and enable the functionality of QTextEngine::indexAdditionalFormats() and QTextEngine::resolveAdditionalFormats(). Thanks to that, we can greatly speed up QTextEngine::format(), which now uses an amort O(1) hash table lookup instead of a O(N) linear search. The added benchmark shows a gain in the order of one magnitude: ./tst_bench_QText formattedLayout:long-many before applying the patch: 378.19 msecs per iteration (total: 37,820, iterations: 100) after applying the patch: 25.80 msecs per iteration (total: 2,580, iterations: 100) Note: This change is source-incompatible for applications using the private QTextEngine API. Task-number: QTBUG-8389 Change-Id: Ifcf7a8902a394428979ea06a6d955f886ee739c7 Reviewed-by: Konstantin Ritt <firstname.lastname@example.org> Reviewed-by: Olivier Goffart <email@example.com> Reviewed-by: Lars Knoll <firstname.lastname@example.org>
Diffstat (limited to 'src/plugins')
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