Hello,
On 2007-October-17 , at 20:24 , Peter Hillier-Brook wrote:
Could someone offer guidance as to why a bitmap (PNG) measuring 600 x 350 px becomes 640 x 373 px after a round trip through Inkscape 0.45?
I'm running on Windows XP SP2 and my objective is to add some drawing elements to a bitmap image (in their own layer(s) and within the dimensions of the bitmap). The original image was created at 96dpi, however it appears to "grow" on import to Inkscape. Inkscape preferences are also set to export at 96dpi, resulting in the over-sized new bitmap.
This is a limitation of Inkscape's current bitmap import: it does not read the dpi of the image and just display all pixels. Inkscape's 1- to-1 resolution is 90 dpi so a 180 dpi image would appear twice as big as it really is when imported into Inkscape. When you export back, the size of the image is not changed and if you export to a resolution different from 90 dpi, the image is resampled to match this resolution (but not resized). In your case 96 -> 90 dpi makes the image grow by 6% and 600*106% =640. Hence the new size. The only workaround is to resize the image manually in Inkscape after import (in the selector toolbar, click the lock and enter 600 in the width field).
I added a FAQ for this: http://wiki.inkscape.org/wiki/index.php/FAQ#Why_do_images_.27grow. 27_when_imported_into_Inkscape.3F Please correct my english (or anything else) if necessary.
JiHO --- http://jo.irisson.free.fr/