72 lines
2.0 KiB
Go
72 lines
2.0 KiB
Go
package pixel
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import (
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"image"
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"image/draw"
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"github.com/faiface/pixel/pixelgl"
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"github.com/pkg/errors"
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)
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// Picture is a raster picture. It is usually used with sprites.
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//
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// A picture is created from an image.Image, that can be either loaded from a file, or generated. After the creation
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// a picture can be sliced (slicing creates a "sub-picture" from a picture) into smaller pictures.
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type Picture struct {
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texture *pixelgl.Texture
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bounds Rect
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}
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// NewPicture creates a new picture from an image.Image.
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func NewPicture(img image.Image) Picture {
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// convert the image to RGBA format
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rgba := image.NewRGBA(image.Rect(0, 0, img.Bounds().Dx(), img.Bounds().Dy()))
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draw.Draw(rgba, rgba.Bounds(), img, img.Bounds().Min, draw.Src)
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texture, err := pixelgl.NewTexture(
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pixelgl.NoOpDoer,
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img.Bounds().Dx(),
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img.Bounds().Dy(),
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rgba.Pix,
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)
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if err != nil {
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panic(errors.Wrap(err, "failed to create picture"))
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}
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return Picture{
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texture: texture,
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bounds: R(0, 0, float64(texture.Width()), float64(texture.Height())),
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}
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}
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// IsNil returns true if a picture is no picture.
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func (p Picture) IsNil() bool {
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return p.texture == nil
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}
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// Texture returns a pointer to the underlying OpenGL texture of a picture.
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//
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// Note, that the parent of this texture is pixelgl.NoOpDoer.
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func (p Picture) Texture() *pixelgl.Texture {
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return p.texture
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}
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// Slice returns a picture within the supplied rectangle of the original picture. The original and the sliced picture
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// share the same texture.
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//
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// For example, suppose we have a 100x200 pixels picture. If we slice it with rectangle (50, 100, 50, 100), we get
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// the upper-right quadrant of the original picture.
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func (p Picture) Slice(slice Rect) Picture {
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return Picture{
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texture: p.texture,
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bounds: Rect{p.bounds.Pos + slice.Pos, slice.Size},
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}
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}
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// Bounds returns the bounding rectangle of this picture relative to the most original picture.
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//
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// If the original picture gets sliced with the return value of this method, this picture will be obtained.
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func (p Picture) Bounds() Rect {
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return p.bounds
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}
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