MAT (Eclipse Memory Analyzer) - how to view bitmaps from memory dump
I'm analyzing memory usage of my Android app with help of Eclipse Memory Analyzer (also known as MAT). Sometimes I can find strange instances of android.graphics.Bitmap
class, utilizing big portion of heap. Problem is what I can't find source of this bitmaps, no filename, no resourceID, nothing. All information what I can find for bitmap is following:
There is a field mBuffer
with array of image pixels, I assume. But it's in some internal Android format, not PNG.
Question: how can I view image represented by this bitmap from memory dump?
I have found a way to view such bitmaps:
- First, you need to download and install GIMP
- Next, find your
Bitmap
object in MAT, right-click onmBuffer
field, in the popup menu choose "Copy" -> "Save Value To File" menu item and save value of this array to some file - give extension
.data
to that file - launch GIMP, choose "File" -> "Open", select your
.data
file and click Open button - "Load Image from Raw Data" dialog will appear. Here you need to set correct parameters for your bitmap
- first, choose "Image type" as "RGB Alpha" (most Android resources have this image type, but you may need to experiment with other image types)
- second, set correct Width and Height for your bitmap (correct dimensions can be found in the memory dump)
At that point you should already observe preview of original image. If you didn't, you can try to change some other parameters in "Load Image from Raw Data" dialog.
NOTE: to get a width and height of image you can look at mWidth
and mHeight
fields in MAT in attributes section as shown in image in question.
You can convert memory dumps from MAT to png using with ImageMagick on command line.
In MAT
for related Bitmap
object right click mBuffer
field and select "Copy" -> "Save Value To File", name the file with an .rgba
extension.
You need to note bitmap width and height from mWidth
and mHeight
fields, which you can see in Bitmap object.
Having ImageMagick
command line tools installed (for Ubuntu apt-get install imagemagick
), you issue convert
command with the following parameters.
convert -size 'width'x'height' -depth 8 filename.rgba filename.png
For example
convert -size 680x1209 -depth 8 phone_decor.rgba phone_decor.png
You can check generated png file via eog, like eog phone_decor.rgba
on Ubuntu
easily.