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fix: Fix hyphenation and rendering of decomposed characters (#1037)

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## Summary

* This PR fixes decomposed diacritic handling end-to-end:
- Hyphenation: normalize common Latin base+combining sequences to
precomposed codepoints before Liang pattern matching, so decomposed
words hyphenate correctly
- Rendering: correct combining-mark placement logic so non-spacing marks
are attached to the preceding base glyph in normal and rotated text
rendering paths, with corresponding text-bounds consistency updates.
- Hyphenation around non breaking space variants have been fixed (and
extended)
- Hyphenation of terms that already included of hyphens were fixed to
include Liang pattern application (eg "US-Satellitensystem" was
*exclusively* broken at the existing hyphen)

## Additional Context

* Before
<img width="800" height="480" alt="2"
src="https://github.com/user-attachments/assets/b9c515c4-ab75-45cc-8b52-f4d86bce519d"
/>


* After
<img width="480" height="800" alt="fix1"
src="https://github.com/user-attachments/assets/4999f6a8-f51c-4c0a-b144-f153f77ddb57"
/>
<img width="800" height="480" alt="fix2"
src="https://github.com/user-attachments/assets/7355126b-80c7-441f-b390-4e0897ee3fb6"
/>

* Note 1: the hyphenation fix is not a 100% bullet proof implementation.
It adds composition of *common* base+combining sequences (e.g. O +
U+0308 -> Ö) during codepoint collection. A complete solution would
require implementing proper Unicode normalization (at least NFC,
possibly NFKC in specific cases) before hyphenation and rendering,
instead of hand-mapping a few combining marks. That was beyond the scope
of this fix.

* Note 2: the render fix should be universal and not limited to the
constraints outlined above: it properly x-centers the compund glyph over
the previous one, and it uses at least 1pt of visual distance in y.

Before:
<img width="478" height="167" alt="Image"
src="https://github.com/user-attachments/assets/f8db60d5-35b1-4477-96d0-5003b4e4a2a1"
/>

After: 
<img width="479" height="180" alt="Image"
src="https://github.com/user-attachments/assets/1b48ef97-3a77-475a-8522-23f4aca8e904"
/>

* This should resolve the issues described in #998 
---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**PARTIALLY**_
This commit is contained in:
jpirnay
2026-02-22 03:11:07 +01:00
committed by GitHub
parent 10a2678584
commit 5f5561b684
8 changed files with 459 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

91
lib/GfxRenderer/GfxRenderer.cpp
View File

@@ -157,10 +157,12 @@ static void renderCharImpl(const GfxRenderer& renderer, GfxRenderer::RenderMode
}
}
if constexpr (rotation == TextRotation::Rotated90CW) {
*cursorY -= glyph->advanceX;
} else {
*cursorX += glyph->advanceX;
if (!utf8IsCombiningMark(cp)) {
if constexpr (rotation == TextRotation::Rotated90CW) {
*cursorY -= glyph->advanceX;
} else {
*cursorX += glyph->advanceX;
}
}
}
@@ -212,6 +214,11 @@ void GfxRenderer::drawText(const int fontId, const int x, const int y, const cha
const EpdFontFamily::Style style) const {
int yPos = y + getFontAscenderSize(fontId);
int xpos = x;
int lastBaseX = x;
int lastBaseY = yPos;
int lastBaseAdvance = 0;
int lastBaseTop = 0;
bool hasBaseGlyph = false;
// cannot draw a NULL / empty string
if (text == nullptr || *text == '\0') {
@@ -224,9 +231,43 @@ void GfxRenderer::drawText(const int fontId, const int x, const int y, const cha
return;
}
const auto& font = fontIt->second;
constexpr int MIN_COMBINING_GAP_PX = 1;
uint32_t cp;
while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
if (utf8IsCombiningMark(cp) && hasBaseGlyph) {
const EpdGlyph* combiningGlyph = font.getGlyph(cp, style);
if (!combiningGlyph) {
combiningGlyph = font.getGlyph(REPLACEMENT_GLYPH, style);
}
int raiseBy = 0;
if (combiningGlyph) {
const int currentGap = combiningGlyph->top - combiningGlyph->height - lastBaseTop;
if (currentGap < MIN_COMBINING_GAP_PX) {
raiseBy = MIN_COMBINING_GAP_PX - currentGap;
}
}
int combiningX = lastBaseX + lastBaseAdvance / 2;
int combiningY = lastBaseY - raiseBy;
renderChar(font, cp, &combiningX, &combiningY, black, style);
continue;
}
const EpdGlyph* glyph = font.getGlyph(cp, style);
if (!glyph) {
glyph = font.getGlyph(REPLACEMENT_GLYPH, style);
}
if (!utf8IsCombiningMark(cp)) {
lastBaseX = xpos;
lastBaseY = yPos;
lastBaseAdvance = glyph ? glyph->advanceX : 0;
lastBaseTop = glyph ? glyph->top : 0;
hasBaseGlyph = true;
}
renderChar(font, cp, &xpos, &yPos, black, style);
}
}
@@ -864,6 +905,9 @@ int GfxRenderer::getTextAdvanceX(const int fontId, const char* text, const EpdFo
int width = 0;
const auto& font = fontIt->second;
while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
if (utf8IsCombiningMark(cp)) {
continue;
}
const EpdGlyph* glyph = font.getGlyph(cp, style);
if (!glyph) glyph = font.getGlyph(REPLACEMENT_GLYPH, style);
if (glyph) width += glyph->advanceX;
@@ -917,9 +961,48 @@ void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y
int xPos = x;
int yPos = y;
int lastBaseX = x;
int lastBaseY = y;
int lastBaseAdvance = 0;
int lastBaseTop = 0;
bool hasBaseGlyph = false;
constexpr int MIN_COMBINING_GAP_PX = 1;
uint32_t cp;
while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
if (utf8IsCombiningMark(cp) && hasBaseGlyph) {
const EpdGlyph* combiningGlyph = font.getGlyph(cp, style);
if (!combiningGlyph) {
combiningGlyph = font.getGlyph(REPLACEMENT_GLYPH, style);
}
int raiseBy = 0;
if (combiningGlyph) {
const int currentGap = combiningGlyph->top - combiningGlyph->height - lastBaseTop;
if (currentGap < MIN_COMBINING_GAP_PX) {
raiseBy = MIN_COMBINING_GAP_PX - currentGap;
}
}
int combiningX = lastBaseX - raiseBy;
int combiningY = lastBaseY - lastBaseAdvance / 2;
renderCharImpl<TextRotation::Rotated90CW>(*this, renderMode, font, cp, &combiningX, &combiningY, black, style);
continue;
}
const EpdGlyph* glyph = font.getGlyph(cp, style);
if (!glyph) {
glyph = font.getGlyph(REPLACEMENT_GLYPH, style);
}
if (!utf8IsCombiningMark(cp)) {
lastBaseX = xPos;
lastBaseY = yPos;
lastBaseAdvance = glyph ? glyph->advanceX : 0;
lastBaseTop = glyph ? glyph->top : 0;
hasBaseGlyph = true;
}
renderCharImpl<TextRotation::Rotated90CW>(*this, renderMode, font, cp, &xPos, &yPos, black, style);
}
}