53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
package typeset
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import "image"
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import "unicode"
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import "image/draw"
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import "image/color"
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import "golang.org/x/image/math/fixed"
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// Drawer is an extended TypeSetter that is able to draw text. Much like
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// TypeSetter, It has no constructor and its zero value can be used safely.
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type Drawer struct { TypeSetter }
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// Draw draws the drawer's text onto the specified canvas at the given offset.
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func (drawer Drawer) Draw (
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destination draw.Image,
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color color.Color,
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offset image.Point,
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) (
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updatedRegion image.Rectangle,
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) {
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source := image.NewUniform(color)
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drawer.For (func (
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index int,
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char rune,
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position fixed.Point26_6,
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) bool {
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destinationRectangle,
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mask, maskPoint, _, ok := drawer.face.Glyph (
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fixed.P (
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offset.X + position.X.Round(),
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offset.Y + position.Y.Round()),
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char)
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if !ok || unicode.IsSpace(char) || char == 0 {
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return true
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}
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// FIXME:? clip destination rectangle if we are on the cusp of
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// the maximum height.
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draw.DrawMask (
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destination,
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destinationRectangle,
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source, image.Point { },
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mask, maskPoint,
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draw.Over)
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updatedRegion = updatedRegion.Union(destinationRectangle)
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return true
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})
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return
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}
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