From 0a2aec7f4826408f4fd25547367da31ed45ac672 Mon Sep 17 00:00:00 2001
From: Rye Mutt <rye@alchemyviewer.org>
Date: Sun, 1 May 2022 17:55:15 -0400
Subject: [PATCH] Heavily improve kerning and font rendering in general with
modern freetype
---
indra/llrender/llfontfreetype.cpp | 53 ++++++++++++++-----------------
indra/llrender/llfontfreetype.h | 2 ++
indra/llrender/llfontgl.cpp | 19 -----------
3 files changed, 25 insertions(+), 49 deletions(-)
diff --git a/indra/llrender/llfontfreetype.cpp b/indra/llrender/llfontfreetype.cpp
index 91e0eb8e519..636d1408271 100644
--- a/indra/llrender/llfontfreetype.cpp
+++ b/indra/llrender/llfontfreetype.cpp
@@ -230,7 +230,7 @@ BOOL LLFontFreetype::loadFace(const std::string& filename, F32 point_size, F32 v
x_max = mFTFace->bbox.xMax * pixels_per_unit;
x_min = mFTFace->bbox.xMin * pixels_per_unit;
mAscender = mFTFace->ascender * pixels_per_unit;
- mDescender = -mFTFace->descender * pixels_per_unit;
+ mDescender = -(mFTFace->descender * pixels_per_unit);
mLineHeight = mFTFace->height * pixels_per_unit;
S32 max_char_width = ll_round(0.5f + (x_max - x_min));
@@ -332,7 +332,7 @@ F32 LLFontFreetype::getDescenderHeight() const
F32 LLFontFreetype::getXAdvance(llwchar wch) const
{
if (mFTFace == NULL)
- return 0.0;
+ return 0.f;
// Return existing info only if it is current
LLFontGlyphInfo* gi = getGlyphInfo(wch);
@@ -356,40 +356,22 @@ F32 LLFontFreetype::getXAdvance(llwchar wch) const
F32 LLFontFreetype::getXAdvance(const LLFontGlyphInfo* glyph) const
{
if (mFTFace == NULL)
- return 0.0;
+ return 0.f;
return glyph->mXAdvance;
}
F32 LLFontFreetype::getXKerning(llwchar char_left, llwchar char_right) const
{
- if (mFTFace == NULL)
- return 0.0;
-
- //llassert(!mIsFallback);
LLFontGlyphInfo* left_glyph_info = getGlyphInfo(char_left);;
- U32 left_glyph = left_glyph_info ? left_glyph_info->mGlyphIndex : 0;
- // Kern this puppy.
LLFontGlyphInfo* right_glyph_info = getGlyphInfo(char_right);
- U32 right_glyph = right_glyph_info ? right_glyph_info->mGlyphIndex : 0;
-
- F32 kerning = 0.0f;
- if (getKerningCache(left_glyph, right_glyph, kerning))
- return kerning;
-
- FT_Vector delta;
-
- llverify(!FT_Get_Kerning(mFTFace, left_glyph, right_glyph, FT_KERNING_DEFAULT, &delta));
-
- kerning = delta.x*(1.f/64.f);
- setKerningCache(left_glyph, right_glyph, kerning);
- return kerning;
+ return getXKerning(left_glyph_info, right_glyph_info);
}
F32 LLFontFreetype::getXKerning(const LLFontGlyphInfo* left_glyph_info, const LLFontGlyphInfo* right_glyph_info) const
{
if (mFTFace == nullptr)
- return 0.0;
+ return 0.f;
U32 left_glyph = left_glyph_info ? left_glyph_info->mGlyphIndex : 0;
U32 right_glyph = right_glyph_info ? right_glyph_info->mGlyphIndex : 0;
@@ -398,11 +380,20 @@ F32 LLFontFreetype::getXKerning(const LLFontGlyphInfo* left_glyph_info, const LL
if (getKerningCache(left_glyph, right_glyph, kerning))
return kerning;
- FT_Vector delta;
+ FT_Vector delta;
+ delta.x = delta.y = 0;
+ if(FT_HAS_KERNING(mFTFace))
+ FT_Get_Kerning(mFTFace, left_glyph, right_glyph, FT_KERNING_UNFITTED, &delta);
- llverify(!FT_Get_Kerning(mFTFace, left_glyph, right_glyph, FT_KERNING_DEFAULT, &delta));
+ if (!FT_IS_SCALABLE(mFTFace))
+ kerning = static_cast<float>(delta.x);
+ else
+ {
+ S32 left_delta = left_glyph_info ? left_glyph_info->mRightSideBearingDelta : 0;
+ S32 right_delta = right_glyph_info ? right_glyph_info->mLeftSideBearingDelta : 0;
+ kerning = llfloor((right_delta - left_delta + static_cast<float>(delta.x) + 32) / 64.f);
+ }
- kerning = delta.x*(1.f/64.f);
setKerningCache(left_glyph, right_glyph, kerning);
return kerning;
}
@@ -470,8 +461,10 @@ LLFontGlyphInfo* LLFontFreetype::addGlyphFromFont(const LLFontFreetype *fontp, l
gi->mXBearing = fontp->mFTFace->glyph->bitmap_left;
gi->mYBearing = fontp->mFTFace->glyph->bitmap_top;
// Convert these from 26.6 units to float pixels.
- gi->mXAdvance = fontp->mFTFace->glyph->advance.x / 64.f;
- gi->mYAdvance = fontp->mFTFace->glyph->advance.y / 64.f;
+ gi->mXAdvance = fontp->mFTFace->glyph->advance.x * (1.f/64.f);
+ gi->mYAdvance = fontp->mFTFace->glyph->advance.y * (1.f/64.f);
+ gi->mRightSideBearingDelta = fontp->mFTFace->glyph->rsb_delta;
+ gi->mLeftSideBearingDelta = fontp->mFTFace->glyph->lsb_delta;
insertGlyphInfo(wch, gi);
@@ -583,10 +576,10 @@ void LLFontFreetype::renderGlyph(U32 glyph_index) const
if (mFTFace == NULL)
return;
- if (FT_Load_Glyph(mFTFace, glyph_index, FT_LOAD_DEFAULT | FT_LOAD_RENDER | FT_LOAD_TARGET_LIGHT) != 0)
+ if (FT_Load_Glyph(mFTFace, glyph_index, FT_LOAD_DEFAULT | FT_LOAD_RENDER | FT_LOAD_FORCE_AUTOHINT) != 0)
{
// If glyph fails to load and/or render, render a fallback character
- llassert_always(!FT_Load_Char(mFTFace, static_cast<FT_ULong>('?'), FT_LOAD_RENDER | FT_LOAD_TARGET_LIGHT));
+ llassert_always(!FT_Load_Char(mFTFace, static_cast<FT_ULong>('?'), FT_LOAD_DEFAULT || FT_LOAD_RENDER | FT_LOAD_FORCE_AUTOHINT));
}
mRenderGlyphCount++;
diff --git a/indra/llrender/llfontfreetype.h b/indra/llrender/llfontfreetype.h
index cd8705f1934..9507ef0c90f 100644
--- a/indra/llrender/llfontfreetype.h
+++ b/indra/llrender/llfontfreetype.h
@@ -91,6 +91,8 @@ struct LLFontGlyphInfo
S32 mXBearing; // Distance from baseline to left in pixels
S32 mYBearing; // Distance from baseline to top in pixels
S32 mBitmapNum; // Which bitmap in the bitmap cache contains this glyph
+ S32 mRightSideBearingDelta;
+ S32 mLeftSideBearingDelta;
};
extern LLFontManager *gFontManagerp;
diff --git a/indra/llrender/llfontgl.cpp b/indra/llrender/llfontgl.cpp
index 30ec1c771f4..f1b80797c92 100644
--- a/indra/llrender/llfontgl.cpp
+++ b/indra/llrender/llfontgl.cpp
@@ -355,13 +355,6 @@ S32 LLFontGL::render(const LLWString &wstr, S32 begin_offset, F32 x, F32 y, cons
cur_x += mFontFreetype->getXKerning(fgi, next_glyph);
}
- // Round after kerning.
- // Must do this to cur_x, not just to cur_render_x, otherwise you
- // will squish sub-pixel kerned characters too close together.
- // For example, "CCCCC" looks bad.
- cur_x = (F32)ll_round(cur_x);
- //cur_y = (F32)ll_round(cur_y);
-
cur_render_x = cur_x;
cur_render_y = cur_y;
}
@@ -534,8 +527,6 @@ F32 LLFontGL::getWidthF32(const llwchar* wchars, S32 begin_offset, S32 max_chars
next_glyph = mFontFreetype->getGlyphInfo(next_char);
cur_x += mFontFreetype->getXKerning(fgi, next_glyph);
}
- // Round after kerning.
- cur_x = (F32)ll_round(cur_x);
}
// add in extra pixels for last character's width past its xadvance
@@ -641,9 +632,6 @@ S32 LLFontGL::maxDrawableChars(const llwchar* wchars, F32 max_pixels, S32 max_ch
next_glyph = mFontFreetype->getGlyphInfo(wchars[i+1]);
cur_x += mFontFreetype->getXKerning(fgi, next_glyph);
}
-
- // Round after kerning.
- cur_x = (F32)ll_round(cur_x);
}
if( clip )
@@ -711,9 +699,6 @@ S32 LLFontGL::firstDrawableChar(const llwchar* wchars, F32 max_pixels, S32 text_
// kerning
total_width += mFontFreetype->getXKerning(wchars[i-1], wch);
}
-
- // Round after kerning.
- total_width = (F32)ll_round(total_width);
}
if (drawable_chars == 0)
@@ -793,10 +778,6 @@ S32 LLFontGL::charFromPixelOffset(const llwchar* wchars, S32 begin_offset, F32 t
next_glyph = mFontFreetype->getGlyphInfo(wchars[pos + 1]);
cur_x += mFontFreetype->getXKerning(glyph, next_glyph);
}
-
-
- // Round after kerning.
- cur_x = (F32)ll_round(cur_x);
}
return llmin(max_chars, pos - begin_offset);
--
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