130 lines
2.4 KiB
Go
130 lines
2.4 KiB
Go
package main
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import (
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"image/color"
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"log"
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"math"
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"github.com/hajimehoshi/ebiten/v2"
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"github.com/hajimehoshi/ebiten/v2/vector"
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)
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const width = 512
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const height = 512
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type appOption func(a *app)
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type app struct {
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strokes []stroke
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diameter float32
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canvas *ebiten.Image
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sizeAnchorPos Vec2
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historyIndex uintptr
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}
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func (a *app) Draw(screen *ebiten.Image) {
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screen.Fill(color.White)
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opts := ebiten.DrawImageOptions{}
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screen.DrawImage(a.canvas, &opts)
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cursor := cursorPosition()
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vector.StrokeCircle(
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screen,
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cursor.x,
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cursor.y,
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a.diameter/2,
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3,
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color.White,
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true,
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)
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vector.StrokeCircle(
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screen,
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cursor.x,
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cursor.y,
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a.diameter/2,
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1,
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color.Black,
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true,
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)
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}
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func (a *app) Layout(_, _ int) (screenWidth int, screenHeight int) {
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return width, height
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}
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func (a *app) Update() error {
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is_drawing := drawWhite.isPressed() || drawBlack.isPressed()
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just_started_drawing := drawWhite.isJustPressed() || drawBlack.isJustPressed()
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var clr color.Color
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if drawBlack.isPressed() {
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clr = color.Black
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} else if drawWhite.isPressed() {
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clr = color.White
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}
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if just_started_drawing {
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if clr == nil {
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log.Fatal("drawing color in update is nil") // should never happen
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}
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a.strokes = append(a.strokes, stroke{
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points: []Vec2{},
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width: a.diameter,
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color: clr,
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})
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}
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// TODO current history pointer is not updated as it should
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// TODO tests
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if len(a.strokes) > 0 {
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currentStroke := &a.strokes[len(a.strokes)-1]
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if is_drawing {
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currentStroke.appendIfMoved(cursorPosition())
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currentStroke.drawLast(a.canvas)
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}
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}
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if resize.isJustPressed() {
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a.sizeAnchorPos = cursorPosition()
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}
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if resize.isPressed() {
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prevPos := a.sizeAnchorPos
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currPos := cursorPosition()
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reltivePos := Vec2{
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prevPos.x - currPos.x,
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prevPos.y - currPos.y,
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}
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length := float32(math.Sqrt(
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float64(reltivePos.x) * float64(reltivePos.x) + float64(reltivePos.y) * float64(reltivePos.y),
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))
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a.diameter = length * 2.0
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}
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return nil
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}
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func newApp( opts ...appOption ) app {
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a := app{}
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for _, opt := range opts {
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opt(&a)
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}
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return a
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}
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func main() {
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ebiten.SetWindowTitle("whiteboard")
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ebiten.SetWindowResizingMode(ebiten.WindowResizingModeEnabled)
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ebiten.CursorPosition()
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whiteboardApp := newApp( func(a *app) {
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a.diameter = 10
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a.canvas = ebiten.NewImage(width, height)
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a.canvas.Fill(color.White)
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})
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ebiten.RunGame(&whiteboardApp)
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}
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