I open a png file. I want to crop/ erase portions of the image. I found all sorts of tutorials that teach you to draw a shape on the image and then select the shape and the image together, go to Path> Difference and apply the difference. My question is: does it apply to vector images/ objects only or can it be used to bitmaps as well? Because I didn’t manage to do this on that png file. I did Trace Bitmap and then tried to apply Path> Difference…same result: couldn’t crop/ erase portions of the image. Doesn’t Path> Trace Bitmap transform the bitmap into vector or am I wrong?
On 2013-10-31, riderplus <riderplus@no-mx.forums.opensuse.org> wrote:
> I open a png file. I want to crop/ erase portions of the image. I found
> all sorts of tutorials that teach you to draw a shape on the image and
> then select the shape and the image together, go to Path> Difference and
> apply the difference. My question is: does it apply to vector images/
> objects only or can it be used to bitmaps as well?
I’m confused. Inkscape is a vector graphics editor and PNG is a raster file format. I strongly suspect you’ll have a lot
more success with PNG files by opening them using a raster editor such as GIMP, where cropping can be performed very
easily.
> Because I didn’t
> manage to do this on that png file. I did Trace Bitmap and then tried to
> apply Path> Difference…same result: couldn’t crop/ erase portions of
> the image. Doesn’t Path> Trace Bitmap transform the bitmap into vector
> or am I wrong?
In general image reliable conversion from vector->raster is monodirectional. I wasn’t aware that any software attempted
the raster->vector conversion but even such software exists, I don’t think it’s a good idea at least in concept.
On 10/31/2013 10:29 AM, flymail pecked at the keyboard and wrote:
> On 2013-10-31, riderplus <riderplus@no-mx.forums.opensuse.org> wrote:
>> I open a png file. I want to crop/ erase portions of the image. I found
>> all sorts of tutorials that teach you to draw a shape on the image and
>> then select the shape and the image together, go to Path> Difference and
>> apply the difference. My question is: does it apply to vector images/
>> objects only or can it be used to bitmaps as well?
> I’m confused. Inkscape is a vector graphics editor and PNG is a raster file format. I strongly suspect you’ll have a lot
> more success with PNG files by opening them using a raster editor such as GIMP, where cropping can be performed very
> easily.
>
Or install the graphic program XV which can do nuch more then crop
vector and raster files.
–
Ken
Inkscape will certainly convert a bitmap to a vector image and I have subsequently been able to manipulate the vector image in ways you cannot do with a bitmap. However, it only works well with a small number of colours, each of which has its own layer. The more colours you have the more layers you have to manipulate if you want to edit it.
So unless you are working on a simple logo, for example, I would advise using GIMP to edit a raster image.
If your question pertains to editing bitmaps per se then I agree with the previous several posts that you’re better off with something like GIMP.
However, if your question pertains to simply cropping a bitmap that you’ve already embedded within an Inkscape drawing that’s another question altogether, and I’ve encountered that difficulty many times. I’ve come up with some hurried workarounds, but I suspect that there’s a “right way” that’s a lot simpler and probably better. So far that “right way” has eluded me. If you find it please come back and post here, so I can benefit too.