merge two png pic

[cocobear]

On Aug 5, 3:44 pm, News123 <news... at free.fr> wrote:
> You didn't really tell us why you need one big file, which contains more
> pixel, than you can probably store in RAM
>

In fact I do not need such a big image.
I just want to know the solution.


> Is it for printing?
> Not knwoing your goal makes it difficult to suggest solutions.
>
> Can't you use other image formats like raw RGB or
> What other image formats are supported?
> tiff? Raw? PPM (http://en.wikipedia.org/wiki/Portable_pixmap)?
>

I want to view image use Windows Pic View.

I don't familiar with PPM， photoshop don't support PPM, does PIL
support this format?


> concatenating raw/ppm files with the same width would be really trivial.
>
> so you could use python to create horizontal raw/ppm stripes.
>
> then you could concatenate them without having to have the whole image
> in RAM.
>
> Perhaps there's even converters from ppm to png, that don't need the
> whole image in RAM.
>
>
>
> cocobear wrote:
> > On Aug 4, 3:24 pm, News123 <news... at free.fr> wrote:
> >> Hi,
>
> >> cocobear wrote:
> >>>>>>> Map = Image.new("RGB", (x,y))
> >>>>>>> Map.paste(im, box)
> >>>>>>> Map.paste(im1,box)
> >>>>>>> Map = Map.convert("L", optimize=True, palette=Image.ADAPTIVE)
> >>>>>>> But if thetwopngpicis too big , or if I have tomergemorepic
> >>>>>>> together, I will get MemoryError:
> >>>>>>>>>>>>> Image.new("RGB",(44544,38656))
> >>>> What do you want to do with such a big image? You will run into the same
> >>>> limitation when you are trying to display it.
> >>> I want to download a map from google map with high precision
> >> For me it sounds strange to handle such big files.
>
> >> Is the map you download from Google really that big?
> >> Mostly Google maps uses normally tiles of sizes 256x256 pixel, wich you
> >> have to compose to get the  big image.
>
> > The map I downloaded from Google is small(256x256). These small maps
> > will compose a big image.
>
> >> If your problem is to combine tiles with different palettes, then you
> >> should pobably look at a way to  'unify' the palette of all tiles befor
> >> combining them.
>
> > I think it is impossible to 'unify' all this tiles.
>
> >> Being no expert of PIL I don't know whether this is easily possible though?
>
> >> bye
>
> >> N