[PATCH weston 4/8] protocol: crop & scale RFC v3

Daniel Stone daniel at fooishbar.org
Thu Nov 28 17:51:03 PST 2013


On 26 November 2013 17:19, Jonny Lamb <jonny.lamb at collabora.co.uk> wrote:
> +      <arg name="src_x" type="fixed" summary="source rectangle x"/>
> +      <arg name="src_y" type="fixed" summary="source rectangle y"/>
> +      <arg name="src_width" type="fixed" summary="source rectangle width"/>
> +      <arg name="src_height" type="fixed" summary="source rectangle height"/>

In the same vein as my reply to Bill, I'd really like to see these
changed to int. I have little sympathy for clients which perform
layout such that their buffer_scale doesn't allow them to represent
their scene in integer space.  I also have a very difficult time
imagining that toolkits would actually perform layout like this.

The more practical / less ideological objection is that this is an
invitation for clients to get things very, very wrong.  Using fixed
suggests that partial-pixel co-ordinates are okay (e.g. src_x of 8.5
with a buffer_scale of 3); just how this is supposed to be represented
accurately in hardware, I'm not quite sure.  I don't see any benefit
to this additional complication for both protocol and implementations;
only downsides.


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