103 lines
2.7 KiB
Go
103 lines
2.7 KiB
Go
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package canvas
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import (
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"image/color"
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"math"
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"fyne.io/fyne/v2"
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)
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// Declare conformity with CanvasObject interface
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var _ fyne.CanvasObject = (*Line)(nil)
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// Line describes a colored line primitive in a Fyne canvas.
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// Lines are special as they can have a negative width or height to indicate
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// an inverse slope (i.e. slope up vs down).
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type Line struct {
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Position1 fyne.Position // The current top-left position of the Line
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Position2 fyne.Position // The current bottom-right position of the Line
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Hidden bool // Is this Line currently hidden
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StrokeColor color.Color // The line stroke color
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StrokeWidth float32 // The stroke width of the line
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}
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// Size returns the current size of bounding box for this line object
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func (l *Line) Size() fyne.Size {
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return fyne.NewSize(float32(math.Abs(float64(l.Position2.X)-float64(l.Position1.X))),
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float32(math.Abs(float64(l.Position2.Y)-float64(l.Position1.Y))))
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}
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// Resize sets a new bottom-right position for the line object, then it will then be refreshed.
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func (l *Line) Resize(size fyne.Size) {
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if size == l.Size() {
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return
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}
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if l.Position1.X <= l.Position2.X {
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l.Position2.X = l.Position1.X + size.Width
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} else {
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l.Position1.X = l.Position2.X + size.Width
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}
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if l.Position1.Y <= l.Position2.Y {
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l.Position2.Y = l.Position1.Y + size.Height
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} else {
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l.Position1.Y = l.Position2.Y + size.Height
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}
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Refresh(l)
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}
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// Position gets the current top-left position of this line object, relative to its parent / canvas
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func (l *Line) Position() fyne.Position {
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return fyne.NewPos(fyne.Min(l.Position1.X, l.Position2.X), fyne.Min(l.Position1.Y, l.Position2.Y))
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}
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// Move the line object to a new position, relative to its parent / canvas
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func (l *Line) Move(pos fyne.Position) {
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oldPos := l.Position()
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deltaX := pos.X - oldPos.X
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deltaY := pos.Y - oldPos.Y
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l.Position1 = l.Position1.Add(fyne.NewPos(deltaX, deltaY))
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l.Position2 = l.Position2.Add(fyne.NewPos(deltaX, deltaY))
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repaint(l)
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}
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// MinSize for a Line simply returns Size{1, 1} as there is no
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// explicit content
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func (l *Line) MinSize() fyne.Size {
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return fyne.NewSize(1, 1)
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}
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// Visible returns true if this line// Show will set this circle to be visible is visible, false otherwise
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func (l *Line) Visible() bool {
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return !l.Hidden
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}
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// Show will set this line to be visible
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func (l *Line) Show() {
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l.Hidden = false
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l.Refresh()
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}
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// Hide will set this line to not be visible
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func (l *Line) Hide() {
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l.Hidden = true
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repaint(l)
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}
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// Refresh causes this line to be redrawn with its configured state.
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func (l *Line) Refresh() {
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Refresh(l)
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}
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// NewLine returns a new Line instance
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func NewLine(color color.Color) *Line {
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return &Line{
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StrokeColor: color,
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StrokeWidth: 1,
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}
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}
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