// PresentationApp project imagick.go
package main

import (
	"image"
	. "math"

	"gopkg.in/gographics/imagick.v2/imagick"
)

/*resizeImage() mw fullsize image
newwidth, newheight = size to be resized to
keepSpecSize = return image with exactly the size specified or just the size of the resized image
center = senter the image
*/
func resizeImage(mw *imagick.MagickWand, newWidth, newHeight int, keepSpecSize, center bool) (resmw *imagick.MagickWand) {
	var (
		width, height, origHeight, origWidth int
	)
	origHeight = int(mw.GetImageHeight())
	origWidth = int(mw.GetImageWidth())

	//check if requested size is the same as current size
	if (origHeight != newHeight) || (origWidth != newWidth) {
		// width / height * newheight = newwidth
		if (round((float64(origWidth) / float64(origHeight)) * float64(newHeight))) <= newWidth {
			width = round((float64(origWidth) / float64(origHeight)) * float64(newHeight))
			height = newHeight
		} else {
			// height / width * newwidth = newheight
			height = round((float64(origHeight) / float64(origWidth)) * float64(newWidth))
			width = newWidth
		}
	} else {
		height = newHeight
		width = newWidth
	}

	//new magickwand for resized image
	resmw = imagick.NewMagickWand()

	if !keepSpecSize {
		resmw.NewImage(uint(width), uint(height), imagick.NewPixelWand())
		center = false
	} else {
		//blank image
		resmw.NewImage(uint(newWidth), uint(newHeight), imagick.NewPixelWand())
		if center {
			err = mw.ResizeImage(uint(width), uint(height), imagick.FILTER_LANCZOS, 1)
			if err != nil {
				panic(err)
			}
			//centers image
			resmw.CompositeImage(mw, imagick.COMPOSITE_OP_SRC_OVER, round(float64(newWidth-width)/float64(2)), round(float64(newHeight-height)/float64(2)))
		} else {
			resmw.CompositeImage(mw, imagick.COMPOSITE_OP_SRC_OVER, 0, 0)
		}
	}
	mw.Destroy()
	return resmw

}

//getImage() from imagick to image.RGBA
func (cl cell) getImage(width, height int) (img *image.RGBA) {
	mw := cl.img.GetImage()
	if (width == 0) || (height == 0) {
		width = int(mw.GetImageWidth())
		height = int(mw.GetImageHeight())
	}

	mw = resizeImage(mw, width, height, true, true)
	img = image.NewRGBA(image.Rect(0, 0, int(width), int(height)))
	if img.Stride != img.Rect.Size().X*4 {
		panic("unsupported stride")
	}

	Tpix, _ := mw.ExportImagePixels(0, 0, uint(width), uint(height), "RGBA", imagick.PIXEL_CHAR)
	img.Pix = Tpix.([]uint8)
	mw.Destroy()
	return
}

func round(a float64) int {
	if a < 0 {
		return int(Ceil(a - 0.5))
	}
	return int(Floor(a + 0.5))
}