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LongCatIsLooong authored
Fixes https://github.com/flutter/flutter/issues/131435, #104594, #43400 Needs https://github.com/flutter/engine/pull/48774 (to fix the web test failure). Currently the method we use for text span hit testing `TextPainter.getPositionForOffset` always returns the closest `TextPosition`, even when the given offset is far away from the text. The new TextPaintes method tells you the layout bounds (`width = letterspacing / 2 + x_advance + letterspacing / 2`, `height = font ascent + font descent`) of a character, the PR changes the hit testing implementation such that a TextSpan is only considered hit if the point-down event landed in one of it's character's layout bounds. Potential issues: 1. In theory since the text is baseline aligned, we should use the max ascent and max descent of each character to calculate the height of the text span's hit-test region, in case some characters in the span have to fall back to a different font, but that will be slower and it typically doesn't make a huge difference. This is a breaking change. It also introduces a new finder and a new method `WidgetTester.tapOnText`: `await tester.tapOnText('string to match')` for ease of migration.