On 6/20/2012 9:58 PM, Fred Greer wrote:
> On Wed, 20 Jun 2012 21:23:35 -0700, Knute Johnson wrote:
>
>> On 6/20/2012 5:23 PM, Fred Greer wrote:
>>> On Wed, 20 Jun 2012 08:39:37 -0700, Knute Johnson wrote:
>>>
>>>> On 6/19/2012 7:31 PM, Fred Greer wrote:
>>>>> I have code that used to work perfectly, which processes images in
>>>>> certain ways, and today it suddenly was not working. I hadn't changed
>>>>> the code at all. I tracked the problem down to spurious
>>>>> IllegalArgumentExceptions being thrown by this code:
>>>>>
>>>>> public class ImageUtils {
>>>>>
>>>>> private static float[] BLUR = {0.1111111, 0.1111111, 0.1111111,
>>>>> 0.1111111, 0.1111111, 0.1111111,
>>>>> 0.1111111, 0.1111111, 0.1111111}
>>>>> ...
>>>>> public static BufferedImage blur (BufferedImage img) {
>>>>> Kernel k = new Kernel(3, 3, BLUR);
>>>>> ConvolveOp co = new ConvolveOp(k, ConvolveOp.EDGE_NO_OP,
>>>>> null); BufferedImage dest = new
>>>>> BufferedImage(img.getWidth(),
>>>>> img.getHeight(),img.getType());
>>>>
>>>> Please try just putting BufferedImage.TYPE_INT_ARGB here instead of
>>>> getting the type from the other image and tell us what happens.
>>>
>>> Are 32-bit PNGs loaded via ImageIO.read guaranteed to be ARGB, or at
>>> least compatible with ARGB destination images for the purposes of
>>> ConvolveOp and friends?
>>
>> I am certainly no expert but I would think that a PNG file would create
>> an ARGB image without any problems and I was curious what would happen.
>>
>> The other option is to not even create a new image and just convert the
>> one you have by putting null destination field.
>
> I thought that didn't work, at least for some transformations? At the
> same time, I prefer to minimize mutation and prefer creating new objects.
> There's much less scope for concurrency problems and some other sorts of
> bugs that way, particularly when a single object is used in various
> places and none of them expect it to change because of one of the other
> places.
>

All right then, that's all I've got for you.

--

Knute Johnson