Hi Anna,
I had to cope with the same issue.
I turned the background to transparent with the
``ImageUtilities#maskColor()" function
(--> ImageWorker).
It is not API, but still I am relying on it for now:
======================================================================
import org.geotools.resources.image.ImageUtilities;
...
GridCoverage2D coverage = [...]
Color BLACK = SWTResourceManager.getColor(0x00, 0x00, 0x00);
double[] BG_RGB = new double[] {
BLACK.getRed(),
BLACK.getGreen(),
BLACK.getBlue()
};
RenderedImage renderedImage = ImageUtilities.maskColor(BLACK,
coverage.getRenderedImage());
GridSampleDimension[] bands = GeoToolsUtils.setTransparency(sourceCov,
BLACK_RGB);
GridCoverage2D trCoverage = GRIDCOV_FACTORY.create(
coverage.getName().toString(),
renderedImage, targetBbox, bands, null, null);
======================================================================
This GeoToolsUtils#setTransparency() prepends an alpha band to the existing
RGB dimensions:
you need to match the rendered image color model with the range type of
your coverage:
======================================================================
import org.geotools.coverage.Category
...
public static GridSampleDimension[] setTransparency(GridCoverage2D
gridCov) {
final int N_BANDS = gridCov.getNumSampleDimensions();
final GridSampleDimension[] bandsWithAlpha = new
GridSampleDimension[N_BANDS + 1];
// A
bandsWithAlpha[0] = new GridSampleDimension("alpha", new Category[]
{ Category.NODATA }, 1, 0);
// RGB
for (int i = 0; i < N_BANDS; ++i) {
final List<Category> categories = new ArrayList<>();
categories.add(new Category("band", bandColors,
NumberRange.create(0, 255)));
bandsWithAlpha[i + 1] = new GridSampleDimension(
gridCov.getSampleDimension(0).getDescription().toString(),
categories.toArray(new Category[0]), 1, 0);
}
return bandsWithAlpha;
}
======================================================================
hth,
-Piero
On 19 December 2016 at 11:54, <
geotools-gt2-users-requ...@lists.sourceforge.net> wrote:
>
> Message: 2
> Date: Mon, 19 Dec 2016 11:54:20 +0100
> From: Anna Amat <anna.amat...@gmail.com>
> Subject: [Geotools-gt2-users] rotating raster
> To: geotools-gt2-users <geotools-gt2-users@lists.sourceforge.net>
> Message-ID:
> <
ca+czrevvaxbb8fg1b1mg+3xp_uwuq6cusepwguwg6symavd...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi list,
>
>
> I have reporoduced the ImageLab example but I have rotated the image by
> changing the world file. When displaying the image I get a black border
> where the envelope has no data (see attached file).
> Is there a way to turn it to transparent?
>
>
> Thanks in advance,
------------------------------------------------------------------------------
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today.http://sdm.link/intel
_______________________________________________
GeoTools-GT2-Users mailing list
GeoTools-GT2-Users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
