Does `textPosition` parameter in `IDWriteTextLayout::HitTestTextPosition` means the utf-16 index or the `wchar_t` index

Asked Apr 09 '23 at 23:03

Active Apr 09 '23 at 23:03

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The method IDWriteTextLayout::HitTestTextPosition takes the first parameter as UINT32 textPosition which the docs describe as:

The text position used to get the pixel location.

But I can't fully understand the meaning of text position in this context. Does it mean the utf-16 index so I should use CharNext and CharPrev to advance and decrease the index? Or does it mean the character (aka wchar_t) index which is 2 bytes on Windows? Or does it mean the glyph index which I don't know what is it?

The text position is also in DWRITE_GLYPH_RUN_DESCRIPTION passed to IDWriteTextRenderer::DrawGlyphRun

asked Apr 09 '23 at 23:03

dev65

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It's the character index, so for unicode string `L"blah"`, 0 is b, 1 is l 2 is a and 3 is h. – Simon Mourier Apr 10 '23 at 08:43

Does `textPosition` parameter in `IDWriteTextLayout::HitTestTextPosition` means the utf-16 index or the `wchar_t` index

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