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Java Forum / General / May 2004Out of memory with BufferedImage
Hi, folks! I have a BufferedImage onto which I'm drawing simple lines and polygons, but I want to allow the user to magnify the final graphic and allow, "Zooming-in," on a choice line or polygon. To cater for this magnification, I'd like the graphic to be placed in a JScrollPane, so that, as the user zooms, the graphic can be dragged about. My problem is that, as I magnify, I must double the size of the BufferedImage each time and draw the lines and polygons twice as big; but after a couple of magnifications, the BufferedImage throws an OutOfMemory exception. Is there a simple way to create allocate memory for only a particaly part of a BufferedImage, rather than for the whole thing? (I want neither to use the Image.getScaledInstance() to zoom-in (because of pixellation), nor to increase heap-size to allow for monster BufferedImages.) Thanks, .ed www.EdmundKirwan.com On 17 May 2004 15:45:55 -0700, iamfractal@hotmail.com wrote or quoted >Is there a simple way to create allocate memory for only a particaly >part of a BufferedImage, rather than for the whole thing? You only required in your paint or paintComponent method to draw the part inside the clipBounds You can draw just that part of the model from scratch each time paint is called. Then you only have the vector storage, which does not get bigger when you magnify. If you want to get very clever, you can predraw tiles, and cache them, only redrawing tiles as needed. If you want to get very fancy, you do your redrawing in the background, preemptively guessing which tiles you will need next. see http://mindprod.com/jgloss/repaint.html for more details.  SignatureCanadian Mind Products, Roedy Green. Coaching, problem solving, economical contract programming. See http://mindprod.com/jgloss/jgloss.html for The Java Glossary. > If you want to get very clever, you can predraw tiles, and cache them, > only redrawing tiles as needed. If you want to get very fancy, you do > your redrawing in the background, preemptively guessing which tiles > you will need next. thats like, pretty cool - perry > On 17 May 2004 15:45:55 -0700, iamfractal@hotmail.com wrote or quoted > see http://mindprod.com/jgloss/repaint.html for more details. > Hi, folks! > [quoted text clipped - 10 lines] > but after a couple of magnifications, the BufferedImage throws an > OutOfMemory exception. Read about AffineTransform in the API documentation. /Thomas >Read about AffineTransform in the API documentation. for an intro, see http://mindprod.com/jgloss/affinetransform.html SignatureCanadian Mind Products, Roedy Green. Coaching, problem solving, economical contract programming. See http://mindprod.com/jgloss/jgloss.html for The Java Glossary. > I have a BufferedImage onto which I'm drawing simple lines and > polygons, but I want to allow the user to magnify the final graphic > and allow, "Zooming-in," on a choice line or polygon. You don't need BufferedImage for this, so don't use it! You should just redraw all your lines/poligons every time. -- http://uio.dev.java.net http://reader.imagero.com > Hi, folks! > [quoted text clipped - 10 lines] > but after a couple of magnifications, the BufferedImage throws an > OutOfMemory exception. If you must DIY: what Roedy said. Otherwise, why not use Piccolo? http://www.cs.umd.edu/hcil/piccolo/ The hard graft has already been done for you! alex Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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