85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
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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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col 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(col)
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drawer.ForRunes (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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// leave empty space for space characters
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if unicode.IsSpace(char) {
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return true
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}
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dot := fixed.P (
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offset.X + position.X.Round(),
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offset.Y + position.Y.Round())
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destinationRectangle,
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mask, maskPoint, _, ok := drawer.face.Glyph(dot, char)
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// tofu
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if !ok {
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drawer.drawTofu(char, destination, col, dot)
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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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func (drawer Drawer) drawTofu (
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char rune,
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destination draw.Image,
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col color.Color,
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position fixed.Point26_6,
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) {
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bounds, _ := tofuBounds(drawer.face)
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rectBounds := image.Rect (
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bounds.Min.X.Round(),
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bounds.Min.Y.Round(),
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bounds.Max.X.Round(),
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bounds.Max.Y.Round()).Add(image.Pt(
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position.X.Round(),
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position.Y.Round()))
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for x := rectBounds.Min.X; x < rectBounds.Max.X; x ++ {
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destination.Set(x, rectBounds.Min.Y, col)
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}
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for y := rectBounds.Min.Y; y < rectBounds.Max.Y; y ++ {
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destination.Set(rectBounds.Min.X, y, col)
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destination.Set(rectBounds.Max.X - 1, y, col)
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}
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for x := rectBounds.Min.X; x < rectBounds.Max.X; x ++ {
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destination.Set(x, rectBounds.Max.Y - 1, col)
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}
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}
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