I know how to get a BufferedImage from JComponent, but how to get a BufferedImage from a Component in java ? The emphasis here is an object of the "Component" type rather than JComponent.
I tried the following method, but it return an all black image, what's wrong with it ?
public static BufferedImage Get_Component_Image(Component myComponent,Rectangle region) throws IOException
{
BufferedImage img = new BufferedImage(myComponent.getWidth(), myComponent.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics g = img.getGraphics();
myComponent.paint(g);
g.dispose();
return img;
}
Component
has a method paint(Graphics)
. That method will paint itself on the passed graphics. This is what we are going to use to create the BufferedImage
, because BufferedImage has the handy method getGraphics()
. That returns a Graphics
-object which you can use to draw on the BufferedImage
.
UPDATE: But we have to pre-configure the graphics for the paint method. That's what I found about the AWT Component rendering at java.sun.com:
When AWT invokes this method, the Graphics object parameter is pre-configured with the appropriate state for drawing on this particular component:
- The Graphics object's color is set to the component's foreground property.
- The Graphics object's font is set to the component's font property.
- The Graphics object's translation is set such that the coordinate (0,0) represents the upper left corner of the component.
- The Graphics object's clip rectangle is set to the area of the component that is in need of repainting.
So, this is our resulting method:
public static BufferedImage componentToImage(Component component, Rectangle region) throws IOException
{
BufferedImage img = new BufferedImage(component.getWidth(), component.getHeight(), BufferedImage.TYPE_INT_ARGB_PRE);
Graphics g = img.getGraphics();
g.setColor(component.getForeground());
g.setFont(component.getFont());
component.paintAll(g);
if (region == null)
{
region = new Rectangle(0, 0, img.getWidth(), img.getHeight());
}
return img.getSubimage(region.x, region.y, region.width, region.height);
}
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