mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
14e2d136aa
Here is a new policy of the namespace of minikin. - All components should be in minikin namespace. - All tests are also in minikin namespace and no anonymous namespace. Bug: 29233740 Change-Id: I71a8a35049bb8d624f7a78797231e90fed1e2b8c
81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
/*
|
|
* Copyright (C) 2015 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#define LOG_TAG "Minikin"
|
|
|
|
#include "LayoutUtils.h"
|
|
|
|
namespace minikin {
|
|
|
|
/**
|
|
* For the purpose of layout, a word break is a boundary with no
|
|
* kerning or complex script processing. This is necessarily a
|
|
* heuristic, but should be accurate most of the time.
|
|
*/
|
|
static bool isWordBreakAfter(int c) {
|
|
if (c == ' ' || (c >= 0x2000 && c <= 0x200a) || c == 0x3000) {
|
|
// spaces
|
|
return true;
|
|
}
|
|
// Note: kana is not included, as sophisticated fonts may kern kana
|
|
return false;
|
|
}
|
|
|
|
static bool isWordBreakBefore(int c) {
|
|
// CJK ideographs (and yijing hexagram symbols)
|
|
return isWordBreakAfter(c) || (c >= 0x3400 && c <= 0x9fff);
|
|
}
|
|
|
|
/**
|
|
* Return offset of previous word break. It is either < offset or == 0.
|
|
*/
|
|
size_t getPrevWordBreakForCache(
|
|
const uint16_t* chars, size_t offset, size_t len) {
|
|
if (offset == 0) return 0;
|
|
if (offset > len) offset = len;
|
|
if (isWordBreakBefore(chars[offset - 1])) {
|
|
return offset - 1;
|
|
}
|
|
for (size_t i = offset - 1; i > 0; i--) {
|
|
if (isWordBreakBefore(chars[i]) || isWordBreakAfter(chars[i - 1])) {
|
|
return i;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Return offset of next word break. It is either > offset or == len.
|
|
*/
|
|
size_t getNextWordBreakForCache(
|
|
const uint16_t* chars, size_t offset, size_t len) {
|
|
if (offset >= len) return len;
|
|
if (isWordBreakAfter(chars[offset])) {
|
|
return offset + 1;
|
|
}
|
|
for (size_t i = offset + 1; i < len; i++) {
|
|
// No need to check isWordBreakAfter(chars[i - 1]) since it is checked
|
|
// in previous iteration. Note that isWordBreakBefore returns true
|
|
// whenever isWordBreakAfter returns true.
|
|
if (isWordBreakBefore(chars[i])) {
|
|
return i;
|
|
}
|
|
}
|
|
return len;
|
|
}
|
|
|
|
} // namespace minikin
|