package main import "core:fmt" import "core:image" import "core:image/bmp" import "core:image/png" _ :: png main :: proc () { watermark(input_filename="bliss.png", output_filename="result.bmp") } watermark :: proc (input_filename, output_filename: string, limit := 100) { fmt.println("Loading", input_filename) img, err := image.load_from_file(input_filename) assert(err == nil) fmt.println(img) defer image.destroy(img) assert(img.width * img.height == len(img.pixels.buf) / 4) pixels := transmute ([][4] u8) img.pixels.buf[:len(img.pixels.buf)/4] total := img.width * img.height stride := total / limit i, n: int for i < total { o := pixels[i] c := &pixels[i] switch { case n==0 : /**/ case n%2==0 : c.b = byte(round_up_to(int(c.b), 4) % 256) case : c.g = byte(round_up_to(int(c.g), 3) % 256) } fmt.printfln( "num %2d (%d) | idx %8d | pos %4d,%4d | rgb %2x -> %2x", n, n%3, i, i%img.width, i/img.width, o.rgb, c.rgb, ) i += stride n += 1 } fmt.println("Saving", output_filename) err = bmp.save(output_filename, img) assert(err == nil) fmt.println("All done.") } round_up_to :: proc (value, up: int) -> int { for d in 0..<up do if (value+d)%up==0 do return value+d panic("???") }