Hi,
On 7/9/07, Gustavo Sverzut Barbieri <[EMAIL PROTECTED]> wrote:
> On 7/9/07, Andre Magalhaes <[EMAIL PROTECTED]> wrote:
> > Hey Raster,
> >
> > On 7/9/07, The Rasterman Carsten Haitzler <[EMAIL PROTECTED]> wrote:
> > > On Fri, 6 Jul 2007 18:00:08 -0300 "Andre Magalhaes" <[EMAIL PROTECTED]>
> > > babbled:
> > >
> > > > Hi all,
> > > >
> > > > As this is my first post here, let me introduce myself. I am Andre
> > > > Moreira Magalhaes, aka andrunko, and I work for INdT in Brazil.
> > >
> > > hey andre :)
> > >
> > > > Now let's go to the point. I am working on a project that requires
> > > > that an Evas_Object to have a custom click area. This object is a
> > > > non-retangular object (a circle for eg) with a transparent backgroung.
> > > > When i click on the background of this object, if the click was in a
> > > > transparent area this object shouldn't receive any event. I was
> > > > investigating the Evas code and i found 3 ways that this could be
> > > > done.
> > >
> > > currently evas doesn't do this. in theory it could - but it doesn't.
> > >
> > > > 1 - Change evas_object_was_in_output_rect to always return 0 if the
> > > > rect is in a transparent area of the object (not desired)
> > > > 2 - Change evas_object_event_callback_call to return a boolean value
> > > > indicating if the object handled the event and if not, keep sending
> > > > event to the other objects in the list. If the object handled the
> > > > event, stop there. This would require a lot of changes.
> > > > 3 - Change evas_object_was_in_output_rect to check a for a custom
> > > > "in_output_rect" method on the object, and if this method is set, use
> > > > it to check if the rect is in output rect. This would require a new
> > > > function, evas_object_is_in_output_rect_cb_set (or something similar)
> > > > that could be implemented whenever is needed. If this method is not
> > > > set, check the clip rectangle as it's done today.
> > >
> > > actually i already designed for this. there is an is_inside and was_inside
> > > method for objects. only line and polygon objects provide them and they
> > > just
> > > return 1 - these CAN be called if a point is inside the object rect and
> > > the
> > > code wants to determine if an event is still inside the object based on
> > > private
> > > object data (eg polygon outline, image pixel alpha channel data etc.).
> > > right
> > > now it basically isn't used - but its intent was to be used for this. the
> > > problem is this is actually relatively slow/expensive to do. you probably
> > > also
> > > want a way of enabling or disabling this level of event processing per
> > > object
> > > to save cost. so we probably need to add an object flag to use these
> > > methods,
> > > if they exist, or disable them (disabled by default), then provide
> > > methods for
> > > image objects at the least - then actually use them, if they are
> > > provided, and
> > > the flag is enabled for that object. implementing this won't be too hrd,
> > > but it
> > > won't be trivial. you need to be able to figure otu any x,y co-ord within
> > > the
> > > object and what pixel of the image that may map to based on paremeters of
> > > the
> > > object, then go check that pixel's alpha channel (if the image has an
> > > alpha
> > > channel). for polygon nd line objects you need to do some half-plane point
> > > intersection math (easy but its order(n) where n is the number of sides
> > > of the
> > > polygon). for lines its strange - you might want perfect inclusion, but
> > > that's a
> > > very small space unless its a thick line (doesn't exist currently). for
> > > text...
> > > thats hard as you need to figure out what character is in that x,y
> > > (that's easy)
> > > and then check the character glyph pixels to see if its inside...
> > >
> > > but anyway - i added this mechanism in at the very start but have never
> > > used it
> > > (or really needed it enough to implement the rest of it).
> > hmmm, i didn't know about this is_inside method, it's similar to what
> > i wanted but with some improvements :D. Attached there is a patch to
> > implement it on evas_object_image and edje, and a callback to
> > enable/disable it. I didn't like the name convention but this is
> > something easy to change. I tested it here and it seems to be working.
> > This is my first patch to evas, so please let me know where i can
> > improve. Any comment is welcome
>
>
> + if (x > w || y > h) {
> + return 0;
> + }
>
> coding style, raster likes ((cond1) || (cond2))
Fixed.
>
> + o->engine_data =
> obj->layer->evas->engine.func->image_data_get(obj->layer->evas->engine.data.output,
> +
> o->engine_data,
> + 0,
> + &data);
> + data += (y * w) + x;
> + a = (*data >> 24) & 0xff;
>
> this will not work for engines != 32bpp, like my 16bpp. If not
> existent, we need to write an engine-provided get_pixel(), that give
> normalized 0-255 components.
I imagined that but in the documentation of evas_object_image_data_get it says:
* @return A pointer to the raw data as 32 bit unsigned integer in format ARGB.
I thought that all engines should convert it to 32 bits in this case,
as it's stated on documentation. I am using the same method as
evas_object_image_data_get uses. Please someone could clarify this.
BR
Andrunko
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