Fonts: Prefer using U+FFFD character for fallback instead of '?'. Use U+FF0E dot character to construct an ellipsis if U+002E '.' is not available. (#4269)

This commit is contained in:
ocornut
2021-06-25 15:44:14 +02:00
parent 8ced41570e
commit 38165f420f
4 changed files with 39 additions and 22 deletions

View File

@ -2795,23 +2795,6 @@ void ImFontAtlasBuildFinish(ImFontAtlas* atlas)
for (int i = 0; i < atlas->Fonts.Size; i++)
if (atlas->Fonts[i]->DirtyLookupTables)
atlas->Fonts[i]->BuildLookupTable();
// Ellipsis character is required for rendering elided text. We prefer using U+2026 (horizontal ellipsis).
// However some old fonts may contain ellipsis at U+0085. Here we auto-detect most suitable ellipsis character.
// FIXME: Also note that 0x2026 is currently seldom included in our font ranges. Because of this we are more likely to use three individual dots.
for (int i = 0; i < atlas->Fonts.size(); i++)
{
ImFont* font = atlas->Fonts[i];
if (font->EllipsisChar != (ImWchar)-1)
continue;
const ImWchar ellipsis_variants[] = { (ImWchar)0x2026, (ImWchar)0x0085 };
for (int j = 0; j < IM_ARRAYSIZE(ellipsis_variants); j++)
if (font->FindGlyphNoFallback(ellipsis_variants[j]) != NULL) // Verify glyph exists
{
font->EllipsisChar = ellipsis_variants[j];
break;
}
}
}
// Retrieve list of range (2 int per range, values are inclusive)
@ -3110,8 +3093,9 @@ ImFont::ImFont()
{
FontSize = 0.0f;
FallbackAdvanceX = 0.0f;
FallbackChar = (ImWchar)'?';
FallbackChar = (ImWchar)-1;
EllipsisChar = (ImWchar)-1;
DotChar = (ImWchar)-1;
FallbackGlyph = NULL;
ContainerAtlas = NULL;
ConfigData = NULL;
@ -3142,6 +3126,14 @@ void ImFont::ClearOutputData()
MetricsTotalSurface = 0;
}
static ImWchar FindFirstExistingGlyph(ImFont* font, const ImWchar* candidate_chars, int candidate_chars_count)
{
for (int n = 0; n < candidate_chars_count; n++)
if (font->FindGlyphNoFallback(candidate_chars[n]) != NULL)
return candidate_chars[n];
return (ImWchar)-1;
}
void ImFont::BuildLookupTable()
{
int max_codepoint = 0;
@ -3184,9 +3176,31 @@ void ImFont::BuildLookupTable()
SetGlyphVisible((ImWchar)' ', false);
SetGlyphVisible((ImWchar)'\t', false);
// Setup fall-backs
// Ellipsis character is required for rendering elided text. We prefer using U+2026 (horizontal ellipsis).
// However some old fonts may contain ellipsis at U+0085. Here we auto-detect most suitable ellipsis character.
// FIXME: Note that 0x2026 is rarely included in our font ranges. Because of this we are more likely to use three individual dots.
const ImWchar ellipsis_chars[] = { (ImWchar)0x2026, (ImWchar)0x0085 };
const ImWchar dots_chars[] = { (ImWchar)'.', (ImWchar)0xFF0E };
if (EllipsisChar == (ImWchar)-1)
EllipsisChar = FindFirstExistingGlyph(this, ellipsis_chars, IM_ARRAYSIZE(ellipsis_chars));
if (DotChar == (ImWchar)-1)
DotChar = FindFirstExistingGlyph(this, dots_chars, IM_ARRAYSIZE(dots_chars));
// Setup fallback character
const ImWchar fallback_chars[] = { (ImWchar)IM_UNICODE_CODEPOINT_INVALID, (ImWchar)'?', (ImWchar)' ' };
FallbackGlyph = FindGlyphNoFallback(FallbackChar);
FallbackAdvanceX = FallbackGlyph ? FallbackGlyph->AdvanceX : 0.0f;
if (FallbackGlyph == NULL)
{
FallbackChar = FindFirstExistingGlyph(this, fallback_chars, IM_ARRAYSIZE(fallback_chars));
FallbackGlyph = FindGlyphNoFallback(FallbackChar);
if (FallbackGlyph == NULL)
{
FallbackGlyph = &Glyphs.back();
FallbackChar = FallbackGlyph->Codepoint;
}
}
FallbackAdvanceX = FallbackGlyph->AdvanceX;
for (int i = 0; i < max_codepoint + 1; i++)
if (IndexAdvanceX[i] < 0.0f)
IndexAdvanceX[i] = FallbackAdvanceX;