doodle/lib/render/canvas/draw.go
Noah Petherbridge 0c6c77a423 Lemon-shaped Ellipse Tool (WIP)
* Add initial Ellipse Tool to the Editor Mode. Currently there's
  something wrong with the algorithm and the ellipses have a sort of
  'lemon shape' to them.
* Refactor the IterLine/IterLine2 functions to be more consistent.
  IterLine used to be the raw algorithm that took a bunch of coordinate
  numbers and IterLine2 took two render.Point's and was the main one
  used throughout the app. Now, IterLine takes the two Points and the
  raw algorithm function removed.
2019-07-14 14:18:44 -07:00

78 lines
1.6 KiB
Go

package canvas
import (
"fmt"
"syscall/js"
"git.kirsle.net/apps/doodle/lib/render"
)
// Methods here implement the drawing functions of the render.Engine
// RGBA turns a color into CSS RGBA string.
func RGBA(c render.Color) string {
return fmt.Sprintf("rgba(%d,%d,%d,%f)",
c.Red,
c.Green,
c.Blue,
float64(c.Alpha)/255,
)
}
// Clear the canvas to a certain color.
func (e *Engine) Clear(color render.Color) {
e.canvas.ctx2d.Set("fillStyle", RGBA(color))
e.canvas.ctx2d.Call("fillRect", 0, 0, e.width, e.height)
}
// SetTitle sets the window title.
func (e *Engine) SetTitle(title string) {
js.Global().Get("document").Set("title", title)
}
// DrawPoint draws a pixel.
func (e *Engine) DrawPoint(color render.Color, point render.Point) {
e.canvas.ctx2d.Set("fillStyle", RGBA(color))
e.canvas.ctx2d.Call("fillRect",
int(point.X),
int(point.Y),
1,
1,
)
}
// DrawLine draws a line between two points.
func (e *Engine) DrawLine(color render.Color, a, b render.Point) {
e.canvas.ctx2d.Set("fillStyle", RGBA(color))
for pt := range render.IterLine(a, b) {
e.canvas.ctx2d.Call("fillRect",
int(pt.X),
int(pt.Y),
1,
1,
)
}
}
// DrawRect draws a rectangle.
func (e *Engine) DrawRect(color render.Color, rect render.Rect) {
e.canvas.ctx2d.Set("strokeStyle", RGBA(color))
e.canvas.ctx2d.Call("strokeRect",
int(rect.X),
int(rect.Y),
int(rect.W),
int(rect.H),
)
}
// DrawBox draws a filled rectangle.
func (e *Engine) DrawBox(color render.Color, rect render.Rect) {
e.canvas.ctx2d.Set("fillStyle", RGBA(color))
e.canvas.ctx2d.Call("fillRect",
int(rect.X),
int(rect.Y),
int(rect.W),
int(rect.H),
)
}