[Mesa-dev] [PATCH] xlib: add X error handler around XGetImage() call

[Ian Romanick]

On 07/25/2012 03:23 PM, Brian Paul wrote:
> XGetImage() will generate a BadMatch error if the source window isn't
> visible.  When that happens, create a new XImage.  Fixes piglit 'select'
> test failures with swrast/xlib driver.
>
> NOTE: This is a candidate for the 8.0 branch.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> ---
>   src/mesa/drivers/x11/xm_buffer.c |   29 +++++++++++++++++++++++++++++
>   1 files changed, 29 insertions(+), 0 deletions(-)
>
> diff --git a/src/mesa/drivers/x11/xm_buffer.c b/src/mesa/drivers/x11/xm_buffer.c
> index a7395a3..eb68f94 100644
> --- a/src/mesa/drivers/x11/xm_buffer.c
> +++ b/src/mesa/drivers/x11/xm_buffer.c
> @@ -446,14 +446,43 @@ xmesa_MapRenderbuffer(struct gl_context *ctx,
>         }
>         else {
>            /* this must be a pixmap/window renderbuffer */
> +         int (*old_handler)(XMesaDisplay *, XErrorEvent *);
>            int y2 = rb->Height - y - h;
>
>            assert(xrb->pixmap);
>
> +         /* Install error handler for XGetImage() in case the the window
> +          * isn't mapped.  If we fail we'll create a temporary XImage.
> +          */
> +         mesaXErrorFlag = 0;
> +         old_handler = XSetErrorHandler(mesaHandleXError);
> +
>            /* read pixel data out of the pixmap/window into an XImage */
>            ximage = XGetImage(xrb->Parent->display,
>                               xrb->pixmap, x, y2, w, h,
>                               AllPlanes, ZPixmap);
> +
> +         XSetErrorHandler(old_handler);
> +
> +         if (mesaXErrorFlag) {
> +            /* create new, temporary XImage */
> +            int bytes_per_line =
> +               _mesa_format_row_stride(xrb->Base.Base.Format,
> +                                       xrb->Base.Base.Width);
> +            char *image = (char *) malloc(bytes_per_line *
> +                                          xrb->Base.Base.Height);
> +            ximage = XCreateImage(xrb->Parent->display,
> +                                  xrb->Parent->xm_visual->visinfo->visual,
> +                                  xrb->Parent->xm_visual->visinfo->depth,
> +                                  ZPixmap, /* format */
> +                                  0, /* offset */
> +                                  image, /* data */
> +                                  xrb->Base.Base.Width,
> +                                  xrb->Base.Base.Height,
> +                                  8, /* pad */
> +                                  bytes_per_line);
> +         }
> +
>            if (!ximage) {
>               *mapOut = NULL;
>               *rowStrideOut = 0;
>