feat(#1): initial implementation

resize.go

@@ -0,0 +1,136 @@
+package bimg
+
+/*
+#cgo pkg-config: vips
+#include "vips/vips.h"
+*/
+import "C"
+
+import (
+	"math"
+)
+
+const (
+	BICUBIC Interpolator = iota
+	BILINEAR
+	NOHALO
+)
+
+func Resize(buf []byte, o Options) ([]byte, error) {
+	// detect (if possible) the file type
+
+	defer C.vips_thread_shutdown()
+
+	image, err := vipsRead(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	//var tmpImage *C.struct__VipsImage
+	/*
+		// feed it
+		imageLength := C.size_t(len(buf))
+		imageBuf := unsafe.Pointer(&buf[0])
+		debug("buffer: %s", buf[0])
+
+		C.vips_jpegload_buffer_seq(imageBuf, imageLength, &image)
+	*/
+
+	// defaults
+	if o.Quality == 0 {
+		o.Quality = QUALITY
+	}
+
+	// get WxH
+	inWidth := int(image.Xsize)
+	inHeight := int(image.Ysize)
+
+	// crop
+
+	if o.Crop {
+		left, top := calculateCrop(inWidth, inHeight, o.Width, o.Height, o.Gravity)
+		o.Width = int(math.Min(float64(inWidth), float64(o.Width)))
+		o.Height = int(math.Min(float64(inHeight), float64(o.Height)))
+		image, err = vipsExtract(image, left, top, o.Width, o.Height)
+		if err != nil {
+			return nil, err
+		}
+		//err := C.vips_extract_area_0(image, &tmpImage, C.int(left), C.int(top), C.int(o.Width), C.int(o.Height))
+		//C.g_object_unref(C.gpointer(image))
+		//image = tmpImage
+	}
+
+	// rotate
+	r := Rotation{180}
+	image, err = Rotate(image, r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Finally save
+	//var ptr unsafe.Pointer
+	//length := C.size_t(0)
+
+	//C.vips_jpegsave_custom(image, &ptr, &length, 1, C.int(o.Quality), 0)
+	//C.g_object_unref(C.gpointer(image))
+	//C.g_object_unref(C.gpointer(newImage))
+
+	// get back the buffer
+	//buf = C.GoBytes(ptr, C.int(length))
+	// cleanup
+	//C.g_free(C.gpointer(ptr))
+
+	buf, err = vipsSave(image, vipsSaveOptions{Quality: o.Quality})
+	if err != nil {
+		return nil, err
+	}
+	C.vips_error_clear()
+
+	return buf, nil
+}
+
+type Rotation struct {
+	angle int
+}
+
+func (a Rotation) calculate() int {
+	angle := a.angle
+	divisor := angle % 90
+	if divisor != 0 {
+		angle = a.angle - divisor
+	}
+	return angle
+}
+
+func Rotate(image *C.struct__VipsImage, r Rotation) (*C.struct__VipsImage, error) {
+	//vips := &Vips{}
+	return vipsRotate(image, r.calculate())
+}
+
+const (
+	CENTRE Gravity = iota
+	NORTH
+	EAST
+	SOUTH
+	WEST
+)
+
+func calculateCrop(inWidth, inHeight, outWidth, outHeight int, gravity Gravity) (int, int) {
+	left, top := 0, 0
+	switch gravity {
+	case NORTH:
+		left = (inWidth - outWidth + 1) / 2
+	case EAST:
+		left = inWidth - outWidth
+		top = (inHeight - outHeight + 1) / 2
+	case SOUTH:
+		left = (inWidth - outWidth + 1) / 2
+		top = inHeight - outHeight
+	case WEST:
+		top = (inHeight - outHeight + 1) / 2
+	default:
+		left = (inWidth - outWidth + 1) / 2
+		top = (inHeight - outHeight + 1) / 2
+	}
+	return left, top
+}