package main

import (
	"image"
	"math"
)

// creates a new rectangle with the min height and width from both images
func getMaxDimensions(img1 image.Image, img2 image.Image) image.Rectangle {
	// get dimensions for both images
	size1 := img1.Bounds().Size()
	size2 := img2.Bounds().Size()

	// final image sized from lowest width and height
	width := int(math.Min(float64(size1.X), float64(size2.X)))
	height := int(math.Min(float64(size1.Y), float64(size2.Y)))

	// the dimensions, as Points, of the output image
	upLeft := image.Point{0, 0}
	lowRight := image.Point{width, height}

	return image.Rectangle{upLeft, lowRight}
}

// resizes image using dimensions from config register (nearest neighbour interpolation)
func resize(img image.Image) (resized *image.RGBA) {
	imgSize := img.Bounds().Size()
	dimensions := dimensionsToRectangle(ConfigRegister.OutputWidth, ConfigRegister.OutputHeight)
	xscale := float64(imgSize.X) / float64(dimensions.Max.X)
	yscale := float64(imgSize.Y) / float64(dimensions.Max.Y)
	// creates new rescaled image based on a given image dimensions
	resized = image.NewRGBA(dimensions)
	// get pixels from the original image
	for x := 0; x < dimensions.Max.X; x++ {
		for y := 0; y < dimensions.Max.Y; y++ {
			xp := int(math.Floor(float64(x) * xscale))
			yp := int(math.Floor(float64(y) * yscale))
			pixel := img.At(xp, yp)
			resized.Set(x, y, pixel)
		}
	}
	return
}

// returns a Rectangle of dimensions <width>x<height>
func dimensionsToRectangle(width int, height int) image.Rectangle {
	upLeft := image.Point{0, 0}
	lowRight := image.Point{width, height}
	return image.Rectangle{upLeft, lowRight}
}