renderJpg() color is bluer than expected

[jdenisgiguere]

Current situation

With I use rendegJpg() on a Multiband Tille, the color is not as expected. It is bluer than expected.

renderPng() return an image of the expected color.

See renderJpg() result

and renderPng() result

Expected situation

repnderPng() and renderJpg() should return similar image.

[pomadchin]

Hi! Thanks for reporting, it is a duplicate of #3151; could you upload an original small image that you use to generate pngs / jpgs so we can test against it?

[jdenisgiguere]

Thanks for the super quick follow up!

See:
tiled_U-19OrthoSectorTile1_2012x2012.zip

[pomadchin]

@jdenisgiguere thanks!

[esmeetu]

Same here.

Problem here might be ImageIO recieve a ARGB while geotrellis give us a RGBA.
And i found a workaround:

  def renderJpg(img: MultibandTile) = {
    // get a rgba tile
    val coloredImg = img.color()

    // begin translate from rgba to argb
    val (cols, rows) = (img.cols, img.rows)
    val bi = new BufferedImage(cols, rows, BufferedImage.TYPE_INT_ARGB)
    cfor(0)(_ < cols, _ + 1) { x =>
      cfor(0)(_ < rows, _ + 1) { y =>
        val v = coloredImg.get(x, y)
        val r = (v >> 24) & 0xFF
        val g = (v >> 16) & 0xFF
        val b = (v >> 8) & 0xFF
        val a = v & 0xFF
        bi.setRGB(x, y, a << 24 | r << 16 | g << 8 | b)
      }
    }
    val result = ImageIO.write(bi, "png", new File("img.png"))
    print(result)
  }

here i use BufferedImage.TYPE_INT_ARGB to keep alpha band. However when i write to jpg format, it will output a weird cmyk format and black image. Using png format works well and saves the alpha info.

In the end, i think it had better to make a change in the method toBufferedImage of file ColorMethods. In case we know that tile is RGBA format, we should make a trans in that method. Like this:

  def toBufferedImage: BufferedImage = {
    val bi = new BufferedImage(self.cols, self.rows, BufferedImage.TYPE_INT_ARGB)
    cfor(0)(_ < self.cols, _ + 1) { x =>
      cfor(0)(_ < self.rows, _ + 1) { y =>
        val v = self.get(x, y)
        val r = (v >> 24) & 0xFF
        val g = (v >> 16) & 0xFF
        val b = (v >> 8) & 0xFF
        val a = v & 0xFF
        bi.setRGB(x, y, a << 24 | r << 16 | g << 8 | b)
      }
    }
    bi
  }

but i cannot get a good jpg file. Might be my jvm or library goes wrong, hoping you guys make a try.

[pomadchin]

Hi @esmeetu that was exactly it! Should be fixed in terms of #3278 now.

cc @jdenisgiguere