Revision: 6489
http://sourceforge.net/p/jump-pilot/code/6489
Author: michaudm
Date: 2020-09-16 22:12:30 +0000 (Wed, 16 Sep 2020)
Log Message:
-----------
add code comments
Modified Paths:
--------------
core/trunk/src/com/vividsolutions/jump/workbench/imagery/geotiff/RasterPainter.java
Modified:
core/trunk/src/com/vividsolutions/jump/workbench/imagery/geotiff/RasterPainter.java
===================================================================
---
core/trunk/src/com/vividsolutions/jump/workbench/imagery/geotiff/RasterPainter.java
2020-09-16 09:24:02 UTC (rev 6488)
+++
core/trunk/src/com/vividsolutions/jump/workbench/imagery/geotiff/RasterPainter.java
2020-09-16 22:12:30 UTC (rev 6489)
@@ -18,7 +18,7 @@
double scaleCached;
RenderedOp imgScaled;
RenderedOp imgWindow;
- RenderedOp imgRescaled;
+ //RenderedOp imgRescaled;
// Rescaling parameters
final static double DEFAULT_RESCALINGCONSTANT = 1;
@@ -26,9 +26,6 @@
double rescalingConstant = DEFAULT_RESCALINGCONSTANT;
double rescalingOffset = DEFAULT_RESCALINGOFFSET;
-// private final int VIEWPORT_MINX = 0;
-// private final int VIEWPORT_MINY = 0;
-
boolean enabled = true;
public RasterPainter(GeoReferencedRaster geoRaster)
@@ -47,9 +44,9 @@
}
/**
- * @param image
- * @param constant
- * @param offset
+ * @param image the image to rescale
+ * @param constant multiplication factor
+ * @param offset offset
* @return
*/
private RenderedOp rescale(RenderedOp image, double constant, double offset)
@@ -136,14 +133,15 @@
scaleCached = scale;
}
- // Next, crop the part which is needed out of the scaled image.
- // First compute the ratio of the image outside the viewport
+ // Compute the ratio of the image to crop (located on the left of the
viewport)
double ratio_cropX = (envModel_viewport.getMinX() - geoRaster.getEnvelope()
.getMinX())
/ geoRaster.getEnvelope().getWidth();
+ // Compute the ratio of the image to crop (located on the north of the
viewport)
double ratio_cropY = (geoRaster.getEnvelope().getMaxY() - envModel_viewport
.getMaxY())
/ geoRaster.getEnvelope().getHeight();
+ // Compute the ratio between the complete image and the viewport
double ratio_cropW = envModel_viewport.getWidth()
/ geoRaster.getEnvelope().getWidth();
double ratio_cropH = envModel_viewport.getHeight()
@@ -150,13 +148,13 @@
/ geoRaster.getEnvelope().getHeight();
// Compute crop parameters, applying ratio on the scaled image
- // What is the need for rounding crop paramaters to ints there ?
float raster_cropX = (float) (ratio_cropX * imgScaled.getWidth());
float raster_cropY = (float) (ratio_cropY * imgScaled.getHeight());
float raster_cropW = (float) (ratio_cropW * imgScaled.getWidth());
float raster_cropH = (float) (ratio_cropH * imgScaled.getHeight());
-
+ // Compute the offset to be applied on the scaled image
+ // to shift the image of 1/2 pixel in the upper left direction
double pixelSizeX = geoRaster.getDblModelUnitsPerRasterUnit_X();
double pixelSizeY = geoRaster.getDblModelUnitsPerRasterUnit_Y();
float raster_offsetX = (float)(-0.5*pixelSizeX*scale);
@@ -163,6 +161,7 @@
float raster_offsetY = (float)(-0.5*pixelSizeY*scale);
// left border of the image is on the right of the left border of the
viewport
+ // image is not cropped, it is shifted to the right
if (raster_cropX < 0)
{
raster_offsetX = raster_offsetX-raster_cropX;
@@ -169,15 +168,15 @@
raster_cropX = 0;
}
// upper border of the image is on the bottom of the upper border of the
viewport
+ // image is not cropped, it is shifted to the south
if (raster_cropY < 0)
{
raster_offsetY = raster_offsetY-raster_cropY;
raster_cropY = 0;
}
- raster_cropW = Math.min(raster_cropW, imgScaled.getWidth()
- - (int) raster_cropX);
- raster_cropH = Math.min(raster_cropH, imgScaled.getHeight()
- - (int) raster_cropY);
+ // width and height of the scaled image to be displayed
+ raster_cropW = Math.min(raster_cropW, imgScaled.getWidth() - raster_cropX);
+ raster_cropH = Math.min(raster_cropH, imgScaled.getHeight() -
raster_cropY);
ParameterBlock pb = new ParameterBlock();
pb.addSource(imgScaled);
@@ -216,7 +215,7 @@
g.setComposite(AlphaComposite.SrcOver);
// The image has been translated and scaled by JAI
- // allready. Just draw it with an identity transformation.
+ // already. Just draw it with an identity transformation.
g.drawRenderedImage(imgRescaled, new AffineTransform());
}
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