I've encountered a behaviour change where my code works in 1.48 but not
properly in subsequent versions.
Essentially, I'm displaying an ImageCanvas inside a JPanel, and the image
data is generated programatically. The minimal example code I've got has a
slider that varies the size of the generated image. It starts at some
default size. Now, here's where the behaviour changes:
In 1.48, as expected the generated image displays at the standard
resolution/zoom level (i.e. 1 pixel to 1 pixel), and so when I make the
image larger, the displayed area gets larger, and always contains the
complete image.
In 1.49 and up when I alter the size of the underlying ImageProcess to LESS
than the original size, the complete image is displayed at a zoom level of
1. If, however I make the image LARGER than the original size, the
displayed area on the screen grows to match (i.e. it's the same number of
screen pixels in size as the image), but the image is zoomed in order to
make the number of image pixels displayed the same number as the original
size of the image.
If that's not entirely clear, I've got links below to the Java source, the
complete source and the JAR file:
Source code:
http://www.edwardrosten.com/test_image.javaComplete (source code, makefile, JAR file, plugins.config):
http://www.edwardrosten.com/minimal.tar.gzI'm guessing that I'm doing something wrong with how I change bits of
information after updating the image. In the source code there's a function
makeimage() which returns FloatProcessor images of various sizes. Here's a
sketch of the code extracted from the source file:
class EControlPanel extends JFrame
{
private ImagePlus image; //Reconstructed image
private ImageCanvas canvas;
EControlPanel()
{
image = new ImagePlus();
image.setProcessor(makeimage());
canvas = new ImageCanvas(image);
//More stuff to make the canvas actually display
}
public void update_canvas()
{
image.setProcessor(makeimage());
//Not 100% sure about why I need these or if I do
image.updateImage();
image.updateAndRepaintWindow();
canvas.repaint();
//Update the canvas size and viewport to prevent funny things with
zooming.
canvas.setDrawingSize(image.getWidth(), image.getHeight());
canvas.setSourceRect(new Rectangle(image.getWidth(),
image.getHeight()));
//cargo cult: prod the GUI system to decide whether we need scroll
bars or not
pack();
validate();
}
}
My current hypothesis is that I'm setting things wrong in the update_canvas
function. I've tried adding a setMagnification(1). That doesn't work: it
displays as before but without the zoom, i.e. it just displays a chunk of
the top-left corner of the image that's the same size as the original.
Interestingly though, the canvas does actually increase in size, because
once it gets large enough then scrollbars (which are in the complete source
code) appear,
Does anyone have any ideas on how to make the image display correctly?
-Ed
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