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Improve letter spacing and line heights of high dpi text.
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resolves #1918
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@slime73
slime73 committed Jul 7, 2024
1 parent 05288b3 commit 7a43805
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Showing 7 changed files with 73 additions and 58 deletions.
18 changes: 9 additions & 9 deletions src/modules/font/GenericShaper.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@
#include "Rasterizer.h"
#include "common/Optional.h"

#include <algorithm>

namespace love
{
namespace font
Expand All @@ -48,7 +50,7 @@ void GenericShaper::computeGlyphPositions(const ColoredCodepoints &codepoints, R
// Spacing counter and newline handling.
Vector2 curpos = offset;

int maxwidth = 0;
float maxwidth = 0;
uint32 prevglyph = 0;

if (positions)
Expand Down Expand Up @@ -86,11 +88,10 @@ void GenericShaper::computeGlyphPositions(const ColoredCodepoints &codepoints, R

if (g == '\n')
{
if (curpos.x > maxwidth)
maxwidth = (int)curpos.x;
maxwidth = std::max(maxwidth, curpos.x);

// Wrap newline, but do not output a position for it.
curpos.y += floorf(getHeight() * getLineHeight() + 0.5f);
curpos.y += getCombinedHeight();
curpos.x = offset.x;
prevglyph = 0;
continue;
Expand All @@ -114,7 +115,7 @@ void GenericShaper::computeGlyphPositions(const ColoredCodepoints &codepoints, R
curpos.x += getKerning(prevglyph, g);

GlyphIndex glyphindex;
int advance = getGlyphAdvance(g, &glyphindex);
float advance = getGlyphAdvance(g, &glyphindex);

if (positions)
positions->push_back({ Vector2(curpos.x, curpos.y), glyphindex });
Expand All @@ -124,20 +125,19 @@ void GenericShaper::computeGlyphPositions(const ColoredCodepoints &codepoints, R

// Account for extra spacing given to space characters.
if (g == ' ' && extraspacing != 0.0f)
curpos.x = floorf(curpos.x + extraspacing);
curpos.x += extraspacing;

prevglyph = g;
}

if (curpos.x > maxwidth)
maxwidth = (int)curpos.x;
maxwidth = std::max(maxwidth, curpos.x);

if (info != nullptr)
{
info->width = maxwidth - offset.x;
info->height = curpos.y - offset.y;
if (curpos.x > offset.x)
info->height += floorf(getHeight() * getLineHeight() + 0.5f);
info->height += getCombinedHeight();
}
}

Expand Down
35 changes: 23 additions & 12 deletions src/modules/font/TextShaper.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,7 @@ TextShaper::TextShaper(Rasterizer *rasterizer)
: rasterizers{rasterizer}
, dpiScales{rasterizer->getDPIScale()}
, height(floorf(rasterizer->getHeight() / rasterizer->getDPIScale() + 0.5f))
, pixelHeight(rasterizer->getHeight())
, lineHeight(1)
, useSpacesForTab(false)
{
Expand All @@ -102,6 +103,16 @@ float TextShaper::getHeight() const
return height;
}

float TextShaper::getPixelHeight() const
{
return pixelHeight;
}

float TextShaper::getCombinedHeight() const
{
return floorf(pixelHeight * lineHeight + 0.5f) / rasterizers[0]->getDPIScale();
}

void TextShaper::setLineHeight(float h)
{
lineHeight = h;
Expand All @@ -112,14 +123,14 @@ float TextShaper::getLineHeight() const
return lineHeight;
}

int TextShaper::getAscent() const
float TextShaper::getAscent() const
{
return floorf(rasterizers[0]->getAscent() / rasterizers[0]->getDPIScale() + 0.5f);
return rasterizers[0]->getAscent() / rasterizers[0]->getDPIScale();
}

int TextShaper::getDescent() const
float TextShaper::getDescent() const
{
return floorf(rasterizers[0]->getDescent() / rasterizers[0]->getDPIScale() + 0.5f);
return rasterizers[0]->getDescent() / rasterizers[0]->getDPIScale();
}

float TextShaper::getBaseline() const
Expand All @@ -128,7 +139,7 @@ float TextShaper::getBaseline() const
if (ascent != 0.0f)
return ascent;
else if (rasterizers[0]->getDataType() == font::Rasterizer::DATA_TRUETYPE)
return floorf(getHeight() / 1.25f + 0.5f); // 1.25 is magic line height for true type fonts
return floorf(getPixelHeight() / 1.25f + 0.5f) / rasterizers[0]->getDPIScale(); // 1.25 is magic line height for true type fonts
else
return 0.0f;
}
Expand Down Expand Up @@ -186,13 +197,13 @@ float TextShaper::getKerning(uint32 leftglyph, uint32 rightglyph)
if (r->hasGlyph(leftglyph) && r->hasGlyph(rightglyph))
{
found = true;
k = floorf(r->getKerning(leftglyph, rightglyph) / r->getDPIScale() + 0.5f);
k = r->getKerning(leftglyph, rightglyph) / r->getDPIScale();
break;
}
}

if (!found)
k = floorf(rasterizers[0]->getKerning(leftglyph, rightglyph) / rasterizers[0]->getDPIScale() + 0.5f);
k = rasterizers[0]->getKerning(leftglyph, rightglyph) / rasterizers[0]->getDPIScale();

kerning[packedglyphs] = k;
return k;
Expand All @@ -216,7 +227,7 @@ float TextShaper::getKerning(const std::string &leftchar, const std::string &rig
return getKerning(left, right);
}

int TextShaper::getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex)
float TextShaper::getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex)
{
const auto it = glyphAdvances.find(glyph);
if (it != glyphAdvances.end())
Expand All @@ -242,7 +253,7 @@ int TextShaper::getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex)
}

const auto &r = rasterizers[rasterizeri];
int advance = floorf(r->getGlyphSpacing(realglyph) / r->getDPIScale() + 0.5f);
float advance = r->getGlyphSpacing(realglyph) / r->getDPIScale();

if (glyph == '\t' && realglyph == ' ')
advance *= SPACES_PER_TAB;
Expand All @@ -255,7 +266,7 @@ int TextShaper::getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex)
return advance;
}

int TextShaper::getWidth(const std::string &str)
float TextShaper::getWidth(const std::string& str)
{
if (str.size() == 0) return 0;

Expand All @@ -281,7 +292,7 @@ static size_t findNewline(const ColoredCodepoints &codepoints, size_t start)
return codepoints.cps.size();
}

void TextShaper::getWrap(const ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &lineranges, std::vector<int> *linewidths)
void TextShaper::getWrap(const ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &lineranges, std::vector<float> *linewidths)
{
size_t nextnewline = findNewline(codepoints, 0);

Expand Down Expand Up @@ -325,7 +336,7 @@ void TextShaper::getWrap(const ColoredCodepoints &codepoints, float wraplimit, s
}
}

void TextShaper::getWrap(const std::vector<ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<int> *linewidths)
void TextShaper::getWrap(const std::vector<ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<float> *linewidths)
{
ColoredCodepoints cps;
getCodepointsFromString(text, cps);
Expand Down
22 changes: 13 additions & 9 deletions src/modules/font/TextShaper.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -77,8 +77,8 @@ class TextShaper : public Object

struct TextInfo
{
int width;
int height;
float width;
float height;
};

// This will be used if the Rasterizer doesn't have a tab character itself.
Expand All @@ -92,6 +92,9 @@ class TextShaper : public Object
bool isUsingSpacesForTab() const { return useSpacesForTab; }

float getHeight() const;
float getPixelHeight() const;

float getCombinedHeight() const;

/**
* Sets the line height (which should be a number to multiply the font size by,
Expand All @@ -106,8 +109,8 @@ class TextShaper : public Object
float getLineHeight() const;

// Extra font metrics
int getAscent() const;
int getDescent() const;
float getAscent() const;
float getDescent() const;
float getBaseline() const;

bool hasGlyph(uint32 glyph) const;
Expand All @@ -116,12 +119,12 @@ class TextShaper : public Object
float getKerning(uint32 leftglyph, uint32 rightglyph);
float getKerning(const std::string &leftchar, const std::string &rightchar);

int getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex = nullptr);
float getGlyphAdvance(uint32 glyph, GlyphIndex *glyphindex = nullptr);

int getWidth(const std::string &str);
float getWidth(const std::string &str);

void getWrap(const std::vector<ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<int> *linewidths = nullptr);
void getWrap(const ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &lineranges, std::vector<int> *linewidths = nullptr);
void getWrap(const std::vector<ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<float> *linewidths = nullptr);
void getWrap(const ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &lineranges, std::vector<float> *linewidths = nullptr);

virtual void setFallbacks(const std::vector<Rasterizer *> &fallbacks);

Expand All @@ -140,12 +143,13 @@ class TextShaper : public Object
private:

int height;
int pixelHeight;
float lineHeight;

bool useSpacesForTab;

// maps glyphs to advance and glyph+rasterizer index.
std::unordered_map<uint32, std::pair<int, GlyphIndex>> glyphAdvances;
std::unordered_map<uint32, std::pair<float, GlyphIndex>> glyphAdvances;

// map of left/right glyph pairs to horizontal kerning.
std::unordered_map<uint64, float> kerning;
Expand Down
28 changes: 14 additions & 14 deletions src/modules/font/freetype/HarfbuzzShaper.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,8 @@
#include <hb.h>
#include <hb-ft.h>

#include <algorithm>

namespace love
{
namespace font
Expand Down Expand Up @@ -226,7 +228,7 @@ void HarfbuzzShaper::computeGlyphPositions(const ColoredCodepoints &codepoints,
std::vector<BufferRange> bufferranges;
computeBufferRanges(codepoints, range, bufferranges);

int maxwidth = (int)curpos.x;
float maxwidth = curpos.x;

for (const auto &bufferrange : bufferranges)
{
Expand Down Expand Up @@ -259,11 +261,10 @@ void HarfbuzzShaper::computeGlyphPositions(const ColoredCodepoints &codepoints,
// the glyph list so we can do it manually.
if (clustercodepoint == '\n')
{
if (curpos.x > maxwidth)
maxwidth = (int)curpos.x;
maxwidth = std::max(maxwidth, curpos.x);

// Wrap newline, but do not output a position for it.
curpos.y += floorf(getHeight() * getLineHeight() + 0.5f);
curpos.y += getCombinedHeight();
curpos.x = offset.x;
continue;
}
Expand All @@ -273,7 +274,7 @@ void HarfbuzzShaper::computeGlyphPositions(const ColoredCodepoints &codepoints,
continue;

// This is a glyph index at this point, despite the name.
GlyphIndex gindex = { (int) info.codepoint, (int)bufferrange.index };
GlyphIndex gindex = { (int) info.codepoint, (int) bufferrange.index };

if (clustercodepoint == '\t' && isUsingSpacesForTab())
{
Expand All @@ -300,30 +301,29 @@ void HarfbuzzShaper::computeGlyphPositions(const ColoredCodepoints &codepoints,

// Harfbuzz position coordinate systems are based on the given font.
// Freetype uses 26.6 fixed point coordinates, so harfbuzz does too.
p.position.x += floorf((glyphpos.x_offset >> 6) / dpiScales[0] + 0.5f);
p.position.y += floorf((glyphpos.y_offset >> 6) / dpiScales[0] + 0.5f);
p.position.x += (glyphpos.x_offset >> 6) / dpiScales[bufferrange.index];
p.position.y += (glyphpos.y_offset >> 6) / dpiScales[bufferrange.index];

positions->push_back(p);
}

curpos.x += floorf((glyphpos.x_advance >> 6) / dpiScales[0] + 0.5f);
curpos.y += floorf((glyphpos.y_advance >> 6) / dpiScales[0] + 0.5f);
curpos.x += (glyphpos.x_advance >> 6) / dpiScales[bufferrange.index];
curpos.y += (glyphpos.y_advance >> 6) / dpiScales[bufferrange.index];

// Account for extra spacing given to space characters.
if (clustercodepoint == ' ' && extraspacing != 0.0f)
curpos.x = floorf(curpos.x + extraspacing);
curpos.x += extraspacing;
}
}

if (curpos.x > maxwidth)
maxwidth = (int)curpos.x;
maxwidth = std::max(maxwidth, curpos.x);

if (info != nullptr)
{
info->width = maxwidth - offset.x;
info->height = curpos.y - offset.y;
if (curpos.x > offset.x)
info->height += floorf(getHeight() * getLineHeight() + 0.5f);
info->height += getCombinedHeight();
}
}

Expand Down Expand Up @@ -373,7 +373,7 @@ int HarfbuzzShaper::computeWordWrapIndex(const ColoredCodepoints &codepoints, Ra
glyphpos.y_advance = HB_DIRECTION_IS_VERTICAL(direction) ? tabSpacesAdvanceY : 0;
}

float newwidth = w + floorf((glyphpos.x_advance >> 6) / dpiScales[0] + 0.5f);
float newwidth = w + (glyphpos.x_advance >> 6) / dpiScales[bufferrange.index];

// Don't count trailing spaces in the output width.
if (isWhitespace(clustercodepoint))
Expand Down
16 changes: 8 additions & 8 deletions src/modules/graphics/Font.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -470,23 +470,23 @@ std::vector<Font::DrawCommand> Font::generateVerticesFormatted(const love::font:
vertices.reserve(text.cps.size() * 4);

std::vector<Range> ranges;
std::vector<int> widths;
std::vector<float> widths;
shaper->getWrap(text, wrap, ranges, &widths);

float y = 0.0f;
float maxwidth = 0.0f;

for (int i = 0; i < (int)ranges.size(); i++)
{
const auto& range = ranges[i];
const auto &range = ranges[i];

if (!range.isValid())
{
y += getHeight() * getLineHeight();
y += shaper->getCombinedHeight();
continue;
}

float width = (float) widths[i];
float width = widths[i];
love::Vector2 offset(0.0f, floorf(y));
float extraspacing = 0.0f;

Expand All @@ -506,7 +506,7 @@ std::vector<Font::DrawCommand> Font::generateVerticesFormatted(const love::font:
auto end = start + range.getSize();
float numspaces = std::count(start, end, ' ');
if (width < wrap && numspaces >= 1)
extraspacing = (wrap - width) / numspaces;
extraspacing = floorf((wrap - width) / numspaces);
else
extraspacing = 0.0f;
break;
Expand Down Expand Up @@ -539,7 +539,7 @@ std::vector<Font::DrawCommand> Font::generateVerticesFormatted(const love::font:
drawcommands.insert(drawcommands.end(), firstcmd, newcommands.end());
}

y += getHeight() * getLineHeight();
y += shaper->getCombinedHeight();
}

if (info != nullptr)
Expand Down Expand Up @@ -612,12 +612,12 @@ int Font::getWidth(uint32 glyph)
return shaper->getGlyphAdvance(glyph);
}

void Font::getWrap(const love::font::ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &ranges, std::vector<int> *linewidths)
void Font::getWrap(const love::font::ColoredCodepoints &codepoints, float wraplimit, std::vector<Range> &ranges, std::vector<float> *linewidths)
{
shaper->getWrap(codepoints, wraplimit, ranges, linewidths);
}

void Font::getWrap(const std::vector<love::font::ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<int> *linewidths)
void Font::getWrap(const std::vector<love::font::ColoredString> &text, float wraplimit, std::vector<std::string> &lines, std::vector<float> *linewidths)
{
shaper->getWrap(text, wraplimit, lines, linewidths);
}
Expand Down
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