zntg/ui/renderer.go

package ui

import (
	"image"
	"image/color"

	"opslag.de/schobers/geom"
	"opslag.de/schobers/zntg"
)

type Renderer interface {
	// Events
	PushEvents(t EventTarget, wait bool) bool
	Refresh()
	Stamp() float64 // in seconds

	// Lifetime
	Destroy() error

	// Drawing
	Clear(c color.Color)
	CreateFontPath(path string, size int) (Font, error)
	CreateTexture(m ImageSource) (Texture, error)
	CreateTextureGo(m image.Image, source bool) (Texture, error)
	CreateTexturePath(path string, source bool) (Texture, error)
	CreateTextureTarget(w, h float32) (Texture, error)
	DefaultTarget() Texture
	DrawTexture(t Texture, p geom.RectangleF32)
	DrawTextureOptions(t Texture, p geom.RectangleF32, opts DrawOptions)
	DrawTexturePoint(t Texture, p geom.PointF32)
	DrawTexturePointOptions(t Texture, p geom.PointF32, opts DrawOptions)
	FillRectangle(r geom.RectangleF32, c color.Color)
	Line(p, q geom.PointF32, color color.Color, thickness float32)
	Location() geom.Point
	Move(geom.Point)
	Rectangle(r geom.RectangleF32, c color.Color, thickness float32)
	RenderTo(Texture)
	RenderToDisplay()
	Resize(width, height int)
	SetIcon(source ImageSource)
	SetMouseCursor(c MouseCursor)
	Size() geom.Point
	Target() Texture
	Text(font Font, p geom.PointF32, color color.Color, text string)
	TextAlign(font Font, p geom.PointF32, color color.Color, text string, align HorizontalAlignment)
	TextTexture(font Font, color color.Color, text string) (Texture, error)
	WindowHandle() uintptr

	// Resources
	Resources() Resources
	SetResourceProvider(resources Resources)
}

// TextTexture renders specified text to a new texture.
func TextTexture(render Renderer, font Font, color color.Color, text string) (Texture, error) {
	target := render.Target()
	defer render.RenderTo(target)
	bounds := font.Measure(text)
	texture, err := render.CreateTextureTarget(bounds.Dx(), bounds.Dy())
	if err != nil {
		return nil, err
	}
	render.RenderTo(texture)
	render.Clear(zntg.MustHexColor(`#00000000`))
	render.Text(font, bounds.Min.Invert(), color, text)
	return texture, nil
}