Memory leak while copying VImage before drawing #2733
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Describe the bug
While trying to do so I get terrible memory leaks. To Reproduce RAM diagnose output of Visual Studio Expected behavior Actual behavior Environment
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Replies: 1 comment 10 replies
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Hi @MathemanFlo,
If you call I think what you need here is I tried: /* compile with
*
* g++ -g -Wall draw.cc `pkg-config vips-cpp --cflags --libs`
*/
#include <vips/vips.h>
#include <vector>
#include <vips/vips8>
using namespace std;
using namespace vips;
int main(int argc, char** argv)
{
VIPS_INIT(argv[0]);
VImage paintLayer = VImage::new_from_file(argv[1]);
vector<double> ink;
ink.push_back(127);
for (int n = 0; n < 100000; ++n)
{
paintLayer = paintLayer.copy_memory();
paintLayer.draw_circle(ink, 10, 10, 10);
}
return 0;
}And it runs in a steady 50mb on this PC. |
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Oh no problem. Doc complaints are very useful: after working on something for a while it all seems so obvious it's impossible to know what bits of the docs are unclear. |
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The documentation itself is more or less sufficient. But to be honest sometimes a few working examples would be great. For example in this case if I would have had a small example how to modify an image using the draw functions then I wouldn't have had the problem. When I started using libvips I had problems with the fact that it sometimes changes the interpretation and the datatype. While it is useful and logical it was not clear to me how to convert it back to uchar or something else. An example would have been great. It was also not so easy to create new images like a mask for the morphological operations. These are not loaded from file (at least I do not do it) and it was not straight forward to create a rectanglar or circular mask. In this case an example would have been great that shows how to use the morphological functions. But in most cases the documentation is absolutely sufficient. |
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I tried adding some more notes to the morph docs and linking to some other mask creator functions: 75e6906 I'm not sure where to add more notes about interpretation and format. Any suggestions? |
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... I added some notes to the arithmetic section: 62fee01 |
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Thank you for all the notes. I'm sure it will help lots of people. Love the notes on morph operations because I also learned something new. The notes for interpretation and cast are excellent and definitely on point. I also thought about it yesterday and maybe a usuful place would be https://www.libvips.org/API/current/VipsImage.html. Before using libvips I had no prior experience with glib and hence it was not clear to me how to access the interpretation and all the other properties. I think it is also non obvious how to set them when reading this doc page, i.e. that copy can be used. If the user does not use the plain c interface but the c++ (or other ones) there is a member function called I also thought whether users would benefit from small code examples, i.e. short programms that illustrate some functionality. I'm sure there are lots of small programs scattered around that show something interesting which could be put in a directory. At least I love short working examples I can adapt to my needs. |
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Hi @MathemanFlo,
image = image.copy()adds a null "copy" node to a pipeline. Pixels are copied between the two images, but they will have different metadata, so you can modify one without changing the other. If you do 100 of these in a row, you'll have a pipeline 100 nodes long (!!).If you call
.draw_circle()on a pipeline, it'll allocate a memory area, render the image into it, then draw the circle. This means that every image on your 100 node pipeline will have a separate memory copy of your source image (!!).I think what you need here is
.copy_memory(). This allocates ram, renders the image into it, and returns a new image which wraps that memory area. Because it breaks the pipeline,…