1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
From f25787b72c20e97cdeb74e037dc1ff56a88b45c6 Mon Sep 17 00:00:00 2001
From: Ben Wagner <bungeman@google.com>
Date: Tue, 1 Dec 2020 20:22:00 -0500
Subject: [PATCH] Subpixel anti-aliasing in FreeType 2.8.1+
FreeType 2.8.1 and later always provide some form of subpixel
anti-aliasing.
Bug: skia:10950,skia:6663
Change-Id: I666cc942e73b73073cdabf900c25faa10d9aaf0f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/339861
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
---
src/ports/SkFontHost_FreeType.cpp | 33 ++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index 990eff4f5e..c0aeb792da 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -32,6 +32,7 @@
#include "src/utils/SkMatrix22.h"
#include <memory>
+#include <tuple>
#include <ft2build.h>
#include FT_ADVANCES_H
@@ -147,13 +148,16 @@ public:
// *reinterpret_cast<void**>(&procPtr) = dlsym(self, "proc");
// because clang has not implemented DR573. See http://clang.llvm.org/cxx_dr_status.html .
- FT_Int major, minor, patch;
- FT_Library_Version(fLibrary, &major, &minor, &patch);
+ using Version = std::tuple<FT_Int, FT_Int, FT_Int>;
+ Version version;
+ FT_Library_Version(fLibrary, &std::get<0>(version),
+ &std::get<1>(version),
+ &std::get<2>(version));
#if SK_FREETYPE_MINIMUM_RUNTIME_VERSION >= 0x02070100
fGetVarDesignCoordinates = FT_Get_Var_Design_Coordinates;
#elif SK_FREETYPE_MINIMUM_RUNTIME_VERSION & SK_FREETYPE_DLOPEN
- if (major > 2 || ((major == 2 && minor > 7) || (major == 2 && minor == 7 && patch >= 0))) {
+ if (Version(2,7,0) <= version) {
//The FreeType library is already loaded, so symbols are available in process.
void* self = dlopen(nullptr, RTLD_LAZY);
if (self) {
@@ -166,7 +170,7 @@ public:
#if SK_FREETYPE_MINIMUM_RUNTIME_VERSION >= 0x02070200
FT_Set_Default_Properties(fLibrary);
#elif SK_FREETYPE_MINIMUM_RUNTIME_VERSION & SK_FREETYPE_DLOPEN
- if (major > 2 || ((major == 2 && minor > 7) || (major == 2 && minor == 7 && patch >= 1))) {
+ if (Version(2,7,1) <= version) {
//The FreeType library is already loaded, so symbols are available in process.
void* self = dlopen(nullptr, RTLD_LAZY);
if (self) {
@@ -185,7 +189,7 @@ public:
#if SK_FREETYPE_MINIMUM_RUNTIME_VERSION >= 0x02080000
fLightHintingIsYOnly = true;
#else
- if (major > 2 || ((major == 2 && minor > 8) || (major == 2 && minor == 8 && patch >= 0))) {
+ if (Version(2,8,0) <= version) {
fLightHintingIsYOnly = true;
}
#endif
@@ -194,7 +198,7 @@ public:
#if SK_FREETYPE_MINIMUM_RUNTIME_VERSION >= 0x02080100
fGetVarAxisFlags = FT_Get_Var_Axis_Flags;
#elif SK_FREETYPE_MINIMUM_RUNTIME_VERSION & SK_FREETYPE_DLOPEN
- if (major > 2 || ((major == 2 && minor > 7) || (major == 2 && minor == 7 && patch >= 0))) {
+ if (Version(2,7,0) <= version) {
//The FreeType library is already loaded, so symbols are available in process.
void* self = dlopen(nullptr, RTLD_LAZY);
if (self) {
@@ -204,11 +208,18 @@ public:
}
#endif
- // Setup LCD filtering. This reduces color fringes for LCD smoothed glyphs.
- // The default has changed over time, so this doesn't mean the same thing to all users.
- if (FT_Library_SetLcdFilter(fLibrary, FT_LCD_FILTER_DEFAULT) == 0) {
- fIsLCDSupported = true;
- fLCDExtra = 2; //Using a filter adds one full pixel to each side.
+ fIsLCDSupported =
+ // Subpixel anti-aliasing may be unfiltered until the LCD filter is set.
+ // Newer versions may still need this, so this test with side effects must come first.
+ // The default has changed over time, so this doesn't mean the same thing to all users.
+ (FT_Library_SetLcdFilter(fLibrary, FT_LCD_FILTER_DEFAULT) == 0) ||
+
+ // In 2.8.1 and later FreeType always provides some form of subpixel anti-aliasing.
+ ((SK_FREETYPE_MINIMUM_RUNTIME_VERSION) >= 0x02080100) ||
+ (Version(2,8,1) <= version);
+
+ if (fIsLCDSupported) {
+ fLCDExtra = 2; // Using a filter may require up to one full pixel to each side.
}
}
~FreeTypeLibrary() {
|