// ValidateImgParams validates desired output image parameters.
func ValidateImgParams(imgP *ImgParams) error {
if imgP.Width%constants.TileSize != 0 || imgP.Height%constants.TileSize != 0 {
return fmt.Errorf("width(%d) and height(%d) of the resulting picture"+
" should be multiples of tile size(%d)\n", imgP.Width,
imgP.Height, constants.TileSize)
}
ratioXY := float64(constants.YMax-constants.YMin) / float64(constants.XMax-constants.XMin)
ratioPxPy := float64(imgP.Height) / float64(imgP.Width)
if ratioXY != ratioPxPy {
sugestedWidth := int(float64(imgP.Height) / ratioXY)
msgFmt := "pixel ratio (%2.2f) differs from XY ratio(%2.2f), try" +
" adjusting width to %d\n\n"
return fmt.Errorf(msgFmt, ratioPxPy, ratioXY, sugestedWidth)
}
if imgP.Scaling < 1 {
msgFmt := "scaling factor must be >= 1, currently: `%d`\n"
return fmt.Errorf(msgFmt, imgP.Scaling)
}
if _, err := algos.MapStr2Func(imgP.Algo); err != nil {
return err
}
return nil
}
// BuildImg coordinates tasks between individual tile-processors. It does not
// directly write pixels, only sends tile numbers to calculate to processors.
func BuildImg(imgP *cmdline.ImgParams) *image.RGBA {
f, _ := algos.MapStr2Func(imgP.Algo)
img := image.NewRGBA(image.Rect(0, 0, imgP.Width, imgP.Height))
waitGroup, workerCh := spawnProcessors(imgP.Scaling, img, f)
for py := 0; py < imgP.Height; py += constants.TileSize {
for px := 0; px < imgP.Width; px += constants.TileSize {
// (sur) should I worry about generating to many objects for GC ?
workerCh <- [2]int{py, px}
}
}
close(workerCh)
waitGroup.Wait()
return img
}