zntg/allegro5/bitmap.go

package allegro5

// #include <allegro5/allegro.h>
// #include <stdlib.h>
import "C"

import (
	"fmt"
	"unsafe"
)

// Bitmap represents an in memory bitmap
type Bitmap struct {
	bitmap *C.ALLEGRO_BITMAP
	width  int
	height int
}

type DrawOptions struct {
	Center bool
	Scale  *Scale
	Tint   *Color
}

type Scale struct {
	Horizontal float32
	Vertical   float32
}

// NewBitmap creates a new bitmap of given width and height
func NewBitmap(width, height int) (*Bitmap, error) {
	b := C.al_create_bitmap(C.int(width), C.int(height))
	if nil == b {
		return nil, fmt.Errorf("Error creating bitmap")
	}
	return &Bitmap{b, width, height}, nil
}

// LoadBitmap tries to load the image at the specified path as a bitmap
func LoadBitmap(path string) (*Bitmap, error) {
	p := C.CString(path)
	defer C.free(unsafe.Pointer(p))
	b := C.al_load_bitmap(p)
	if nil == b {
		return nil, fmt.Errorf("Error loading bitmap")
	}
	width := int(C.al_get_bitmap_width(b))
	height := int(C.al_get_bitmap_height(b))
	return &Bitmap{b, width, height}, nil
}

// Draw draws the bitmap at the given location
func (b *Bitmap) Draw(left, top float32) {
	C.al_draw_bitmap(b.bitmap, C.float(left), C.float(top), 0)
}

func (b *Bitmap) DrawOptions(left, top float32, options DrawOptions) {
	width := float32(b.width)
	height := float32(b.height)

	scale := nil != options.Scale
	if scale {
		width *= options.Scale.Horizontal
		height *= options.Scale.Vertical
	}
	if options.Center {
		left -= width * 0.5
		top -= height * 0.5
	}

	if scale {
		if nil == options.Tint {
			C.al_draw_scaled_bitmap(b.bitmap, 0, 0, C.float(b.width), C.float(b.height), C.float(left), C.float(top), C.float(width), C.float(height), 0)
		} else {
			C.al_draw_tinted_scaled_bitmap(b.bitmap, options.Tint.color, 0, 0, C.float(b.width), C.float(b.height), C.float(left), C.float(top), C.float(width), C.float(height), 0)
		}
	} else {
		if nil == options.Tint {
			C.al_draw_bitmap(b.bitmap, C.float(left), C.float(top), 0)
		} else {
			C.al_draw_tinted_bitmap(b.bitmap, options.Tint.color, C.float(left), C.float(top), 0)
		}
	}
}

func (b *Bitmap) Width() int {
	return b.width
}

func (b *Bitmap) Height() int {
	return b.height
}

// Destroy destroys the bitmap
func (b *Bitmap) Destroy() {
	C.al_destroy_bitmap(b.bitmap)
}