67 lines
1.5 KiB
Go
67 lines
1.5 KiB
Go
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package cache
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import (
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"sync"
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"time"
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"fyne.io/fyne/v2"
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)
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var (
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fontSizeCache = map[fontSizeEntry]fontMetric{}
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fontSizeLock = sync.RWMutex{}
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)
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type fontMetric struct {
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expiringCache
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size fyne.Size
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baseLine float32
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}
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type fontSizeEntry struct {
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text string
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size float32
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style fyne.TextStyle
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}
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// GetFontMetrics looks up a calculated size and baseline required for the specified text parameters.
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func GetFontMetrics(text string, fontSize float32, style fyne.TextStyle) (size fyne.Size, base float32) {
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ent := fontSizeEntry{text, fontSize, style}
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fontSizeLock.RLock()
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ret, ok := fontSizeCache[ent]
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fontSizeLock.RUnlock()
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if !ok {
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return fyne.Size{Width: 0, Height: 0}, 0
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}
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ret.setAlive()
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return ret.size, ret.baseLine
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}
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// SetFontMetrics stores a calculated font size and baseline for parameters that were missing from the cache.
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func SetFontMetrics(text string, fontSize float32, style fyne.TextStyle, size fyne.Size, base float32) {
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ent := fontSizeEntry{text, fontSize, style}
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metric := fontMetric{size: size, baseLine: base}
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metric.setAlive()
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fontSizeLock.Lock()
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fontSizeCache[ent] = metric
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fontSizeLock.Unlock()
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}
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// destroyExpiredFontMetrics destroys expired fontSizeCache entries
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func destroyExpiredFontMetrics(now time.Time) {
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expiredObjs := make([]fontSizeEntry, 0, 50)
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fontSizeLock.RLock()
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for k, v := range fontSizeCache {
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if v.isExpired(now) {
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expiredObjs = append(expiredObjs, k)
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}
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}
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fontSizeLock.RUnlock()
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fontSizeLock.Lock()
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for _, k := range expiredObjs {
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delete(fontSizeCache, k)
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}
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fontSizeLock.Unlock()
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}
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