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Re: [E-devel] Premultiply or not

On Tue, 4 Jul 2006 00:11:10 +0900,
Carsten Haitzler (The Rasterman) <raster@rasterman.com> wrote :

> every edje design (.edc's) that specifies a color for text or solids,
> clips etc. any app that sets an object color itself.  there are 74
> calls to evas_object_color_set in e17. e17's creation of netwm icons
> would need to do a premul step. 54 in edje. more in ewl, etk etc.
> etc. now with edje - do we force the .edc's to specify colors in
> premul? if so there are (evil) 666 instances of colors in e17's
> default theme - or do we have edje_cc convert to premul on encode -
> or do we have edje turn into premul runtime?... how far do you go? :)

Etk doesn't often use evas_object_color_set() so it will be really easy
to port. For .edc files, I really think the colors should remain
non-premul RGBA colors since .edc files are made by graphic designers, and
designers are used to non-premul RGBA colors (graphic tools give
non-premul colors). And using premul colors will really make theming
painful imho since themers often try different color settings to see
which setting is the best looking. With premul colors, the themers would
have to convert to premul colors each time they would like to change a

Now, whether edje_cc should convert to premul on compilation or do it on
runtime, I don't really know. Maybe it could be done during the compilation,
so it'll save some work during runtime.

Also, what do you think of having an API like that for image_data_set/get()?
void evas_object_image_data_set(Evas_Object *obj, void *data, Evas_Colorspace colorspace);
void *evas_object_image_data_get(Evas_Object *obj, Evas_Colorspace colorspace, Evas_Bool for_writing);

The "colorspace" param in the data_set() func describes the colorspace
of the given data, and in data_get(), it describes the colorspace in
which you'd like to get the data. The colorspace in which it's stored
by Evas could depend on the engine (it could be "colorspace" if the
engine is optimized for "colorspace", or another more adapted colorspace).
Perhaps that is what you were already discussing with Jose, I haven't
understood very well.

Simon TRENY <MoOM>