[cairo] Unsymmetrical rotation

[Blagoj Kupev]

Hello,
Already tried, and does not work... as i can understand the documentation
the functions cairo_translate and cairo_rotate only modify the current
transformation matrix and then the transformation is applied when the
function cairo_set_source_surface is called. Then as i understand,
cairo_set_source_surface is doing additional matrix transformation with the
x and y offsets prior the matrix is executed.

It seems that:

   cairo_translate (cr, x_origin, y_origin);
   cairo_rotate (cr, (2*3.14*angle/360));
   cairo_set_source_surface(cr, surf1, x, y);

Is the same as:

   cairo_translate (cr, x_origin, y_origin);
   cairo_rotate (cr, (2*3.14*angle/360));
   cairo_translate (cr, x, y);
   cairo_set_source_surface(cr, surf1, 0, 0);

Thanks,
Blagoj

On Sun, Mar 3, 2013 at 9:37 PM, Bill Spitzak <spitzak at gmail.com> wrote:

> On 03/03/2013 06:33 AM, Blagoj Kupev wrote:
>
>     cairo_translate (cr, x_origin, y_origin);
>>    cairo_rotate (cr, (2*3.14*angle/360));
>>
>>    cairo_set_source_surface(cr, surf1, -x_origin+x_offset, -y_origin);
>>    cairo_paint(cr);
>>
>
> I think this will work:
>
>
>     cairo_translate (cr, x_origin, y_origin);
>     cairo_rotate (cr, (2*3.14*angle/360));
>     cairo_translate (cr, x_offset, 0);
>     cairo_set_source_surface(cr, surf1, -x_origin, -y_origin);
>
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