[cairo] [PATCH] gl: Fix offset for non-texture surface patterns

[Andrea Canciani]

On Fri, Nov 4, 2011 at 9:31 PM, Martin Robinson <mrobinson at igalia.com> wrote:
> I'm not entirely certain this patch takes the correct approach, but
> it seems to fix problems with the GL and MSAA compositors when
> filling with a surface source.
>
> Subject: [PATCH] gl: Fix offset for non-texture surface patterns
>
> Instead of drawing only a portion of the image into the intermediate
> texture, draw the entire image and adjust the translation matrix to
> compensate.
> ---
>  src/cairo-gl-operand.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/src/cairo-gl-operand.c b/src/cairo-gl-operand.c
> index a7e187e..bd59d97 100644
> --- a/src/cairo-gl-operand.c
> +++ b/src/cairo-gl-operand.c
> @@ -156,7 +156,7 @@ _cairo_gl_pattern_texture_setup (cairo_gl_operand_t *operand,
>     if (src->surface->backend->type == CAIRO_SURFACE_TYPE_IMAGE) {
>        status = _cairo_gl_surface_draw_image (surface,
>                                      (cairo_image_surface_t *)src->surface,
> -                                     src_x, src_y,
> +                                     0, 0,
>                                      width, height,
>                                      0, 0);
>
> @@ -166,7 +166,7 @@ _cairo_gl_pattern_texture_setup (cairo_gl_operand_t *operand,
>        cairo_surface_t *image;
>
>        image = cairo_surface_map_to_image (&surface->base, NULL);
> -       status = _cairo_surface_offset_paint (image, src_x, src_y,
> +       status = _cairo_surface_offset_paint (image, 0, 0,
>                                              CAIRO_OPERATOR_SOURCE, _src,
>                                              NULL);

I'm not sure if the approach is correct, but, assuming it is, how about simply
using _cairo_surface_paint()?
Using a constant (0,0) offset looks weird to me.

Andrea

>        cairo_surface_unmap_image (&surface->base, image);
> @@ -185,7 +185,7 @@ _cairo_gl_pattern_texture_setup (cairo_gl_operand_t *operand,
>      * (unnormalized src -> unnormalized src) to
>      * (unnormalized dst -> unnormalized src)
>      */
> -    cairo_matrix_init_translate (&m, -dst_x, -dst_y);
> +    cairo_matrix_init_translate (&m, src_x - dst_x, src_y - dst_y);
>     cairo_matrix_multiply (&attributes->matrix, &m, &src->base.matrix);
>
>     /* Translate the matrix from
> --
> 1.7.5.4
>
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