doodle/render/sdl/text.go

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package sdl
import (
"git.kirsle.net/apps/doodle/render"
"github.com/veandco/go-sdl2/sdl"
"github.com/veandco/go-sdl2/ttf"
)
var fonts map[int]*ttf.Font = map[int]*ttf.Font{}
// LoadFont loads and caches the font at a given size.
func LoadFont(size int) (*ttf.Font, error) {
if font, ok := fonts[size]; ok {
return font, nil
}
font, err := ttf.OpenFont("./fonts/DejaVuSansMono.ttf", size)
if err != nil {
return nil, err
}
fonts[size] = font
return font, nil
}
// DrawText draws text on the canvas.
func (r *Renderer) DrawText(text render.Text, rect render.Rect) error {
var (
font *ttf.Font
surface *sdl.Surface
tex *sdl.Texture
err error
)
if font, err = LoadFont(text.Size); err != nil {
return err
}
write := func(dx, dy int32, color sdl.Color) {
if surface, err = font.RenderUTF8Blended(text.Text, color); err != nil {
return
}
defer surface.Free()
if tex, err = r.renderer.CreateTextureFromSurface(surface); err != nil {
return
}
defer tex.Destroy()
tmp := &sdl.Rect{
X: rect.X + dx,
Y: rect.Y + dy,
W: surface.W,
H: surface.H,
}
r.renderer.Copy(tex, nil, tmp)
}
// Does the text have a stroke around it?
if text.Stroke != render.Invisible {
color := ColorToSDL(text.Stroke)
write(-1, -1, color)
write(-1, 0, color)
write(-1, 1, color)
write(1, -1, color)
write(1, 0, color)
write(1, 1, color)
write(0, -1, color)
write(0, 1, color)
}
// Does it have a drop shadow?
if text.Shadow != render.Invisible {
write(1, 1, ColorToSDL(text.Shadow))
}
// Draw the text itself.
write(0, 0, ColorToSDL(text.Color))
return err
}