Graphics.drawImage not using specified background color

[Sam Ingrassia]

Thanks to everyone in advance -

I have created an image resizing class, with a crop method. The cropping works great, the issue that I am having is the background color that i specify in the drawImage function of Graphics is not working correctly, it defaults everything to black. Here is the code below that I am working with, I have also included the SaveTo method so you can see how I am saving as well

Thanks,

Sam

 

			public void Crop(int Height, int Width, int SourceX, int SourceY) throws Exception {
				
				//output height and width
				int OutputWidth = this.OutputImage.getWidth();
				int OutputHeight = this.OutputImage.getHeight();
				
				//create output streams
				ByteArrayOutputStream MyByteArrayOutputStream = new ByteArrayOutputStream();
				MemoryCacheImageOutputStream MyMemoryCacheImageOutputStream = new MemoryCacheImageOutputStream(MyByteArrayOutputStream);
				
				//Create a new  BufferedImage
				BufferedImage NewImage = new BufferedImage(Width, Height, BufferedImage.TYPE_INT_RGB );
				Graphics MyGraphics = NewImage.getGraphics();
				MyGraphics.drawImage(this.OutputImage, -SourceX, -SourceY, OutputWidth, OutputHeight, Color.WHITE, null);
				
				// Get Writer and set compression
				Iterator MyIterator = ImageIO.getImageWritersByFormatName("BMP");
				if(MyIterator.hasNext()) {
					
					//get image writer
					ImageWriter MyImageWriter = (ImageWriter)MyIterator.next();
					
					//get params
					ImageWriteParam MyImageWriteParam = MyImageWriter.getDefaultWriteParam();
					
					//set outputstream
					MyImageWriter.setOutput(MyMemoryCacheImageOutputStream);
					
					//create new ioimage
					IIOImage MyIIOImage = new IIOImage(NewImage, null, null);
					
					//write new image
					MyImageWriter.write(null, MyIIOImage, MyImageWriteParam);
				}
				
				//convert output stream back to inputstream
				ByteArrayInputStream MyByteArrayInputStream = new ByteArrayInputStream(MyByteArrayOutputStream.toByteArray());
				MemoryCacheImageInputStream MyMemoryCacheImageInputStream = new MemoryCacheImageInputStream(MyByteArrayInputStream);
				
				//resassign as a buffered image
				this.OutputImage = ImageIO.read(MyMemoryCacheImageInputStream);
			}

		public void SaveTo(String DirectoryPath) throws Exception {
				if(this.ContentType == "image/gif"){
					ImageIO.write(this.OutputImage, "gif", new File(DirectoryPath + this.ImageName));
				}
				else if(this.ContentType == "image/jpeg"){
					ImageIO.write(this.OutputImage, "jpg", new File(DirectoryPath + this.ImageName));
				}
				else if(this.ContentType == "image/png"){
					ImageIO.write(this.OutputImage, "png", new File(DirectoryPath + this.ImageName));
				}
				else if(this.ContentType == "image/bmp"){
					ImageIO.write(this.OutputImage, "bmp", new File(DirectoryPath + this.ImageName));
				}
				else{
					ImageIO.write(this.OutputImage, "jpg", new File(DirectoryPath + this.ImageName));
				}
				  
			}
 

[Rob Spoor]

Try using BufferedImage.TYPE_INT_ARGB. The background is only used with transparency, and BufferedImage.TYPE_INT_RGB does not support that.

Also, there is an error in your code.

MyGraphics.drawImage(this.OutputImage, -SourceX, -SourceY, OutputWidth, OutputHeight, Color.WHITE, null);

You draw a part of the image of size OutputWidth x OutputHeight, but a part of that rectangle is outside your actual image. You should add SourceX and SourceY to the rectangle to draw:

MyGraphics.drawImage(this.OutputImage, -SourceX, -SourceY, OutputWidth + SourceX, OutputHeight + SourceY, Color.WHITE, null);

Also, don't forget to dispose() your Graphics object.

[Sam Ingrassia]

Thank you very much for the reply -


So I dropped in TYPE_INT_ARGB in and it gave me the error "java.io.IOException: Image can not be encoded with compression type BI_RGB", after looking into that a bit, I set the "getImageWritersByFormatName" to use PNG instead of BMP (I guess BMP doesnt support transparency, or it does, but no one ever implements it). This time though the image that I am overlaying colors were modified and the background is still black : )

Any suggestions?

Thanks,

Sam