Date: Mon, 25 Apr 2016 11:02:55 +0200
From: Daniel Vetter <daniel@ffwll.ch>
To: Noralf =?iso-8859-1?Q?Tr=F8nnes?= <noralf@tronnes.org>
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
        daniel@ffwll.ch, laurent.pinchart@ideasonboard.com,
        tomi.valkeinen@ti.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/8] drm/rect: Add some drm_clip_rect utility functions
Message-ID: <20160425090255.GO2510@phenom.ffwll.local>
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On Sun, Apr 24, 2016 at 10:48:55PM +0200, Noralf Tr?nnes wrote:
> Add some utility functions for struct drm_clip_rect.
> 
> Signed-off-by: Noralf Tr?nnes <noralf@tronnes.org>
> ---
>  drivers/gpu/drm/drm_rect.c | 67 ++++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_rect.h     | 69 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 136 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
> index a8e2c86..a9fb1a8 100644
> --- a/drivers/gpu/drm/drm_rect.c
> +++ b/drivers/gpu/drm/drm_rect.c
> @@ -434,3 +434,70 @@ void drm_rect_rotate_inv(struct drm_rect *r,
>  	}
>  }
>  EXPORT_SYMBOL(drm_rect_rotate_inv);
> +
> +/**
> + * drm_clip_rect_intersect - intersect two clip rectangles
> + * @r1: first clip rectangle
> + * @r2: second clip rectangle
> + *
> + * Calculate the intersection of clip rectangles @r1 and @r2.
> + * @r1 will be overwritten with the intersection.
> + *
> + * RETURNS:
> + * %true if rectangle @r1 is still visible after the operation,
> + * %false otherwise.
> + */
> +bool drm_clip_rect_intersect(struct drm_clip_rect *r1,
> +			     const struct drm_clip_rect *r2)
> +{
> +	r1->x1 = max(r1->x1, r2->x1);
> +	r1->y1 = max(r1->y1, r2->y1);
> +	r1->x2 = min(r1->x2, r2->x2);
> +	r1->y2 = min(r1->y2, r2->y2);
> +
> +	return drm_clip_rect_visible(r1);
> +}
> +EXPORT_SYMBOL(drm_clip_rect_intersect);
> +
> +/**
> + * drm_clip_rect_merge - Merge clip rectangles
> + * @dst: destination clip rectangle
> + * @src: source clip rectangle(s), can be NULL
> + * @num_clips: number of source clip rectangles
> + * @flags: drm_mode_fb_dirty_cmd flags (DRM_MODE_FB_DIRTY_ANNOTATE_COPY)
> + * @width: width of clip rectangle if @src is NULL
> + * @height: height of clip rectangle if @src is NULL
> + *
> + * The dirtyfb ioctl allows for a NULL clip rectangle to be passed in,
> + * so if @src is NULL, width and height is used to set a full clip rectangle.
> + * @dst takes part in the merge unless it is empty {0,0,0,0}.
> + */
> +void drm_clip_rect_merge(struct drm_clip_rect *dst,
> +			 struct drm_clip_rect *src, unsigned num_clips,
> +			 unsigned flags, u32 width, u32 height)
> +{
> +	int i;
> +
> +	if (!src || !num_clips) {
> +		dst->x1 = 0;
> +		dst->x2 = width;
> +		dst->y1 = 0;
> +		dst->y2 = height;
> +		return;
> +	}
> +
> +	if (drm_clip_rect_is_empty(dst)) {
> +		dst->x1 = ~0;
> +		dst->y1 = ~0;
> +	}
> +
> +	for (i = 0; i < num_clips; i++) {
> +		if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY)
> +			i++;
> +		dst->x1 = min(dst->x1, src[i].x1);
> +		dst->x2 = max(dst->x2, src[i].x2);
> +		dst->y1 = min(dst->y1, src[i].y1);
> +		dst->y2 = max(dst->y2, src[i].y2);
> +	}
> +}
> +EXPORT_SYMBOL(drm_clip_rect_merge);
> diff --git a/include/drm/drm_rect.h b/include/drm/drm_rect.h
> index 83bb156..936ad8d 100644
> --- a/include/drm/drm_rect.h
> +++ b/include/drm/drm_rect.h
> @@ -24,6 +24,8 @@
>  #ifndef DRM_RECT_H
>  #define DRM_RECT_H
>  
> +#include <uapi/drm/drm.h>
> +
>  /**
>   * DOC: rect utils
>   *
> @@ -171,4 +173,71 @@ void drm_rect_rotate_inv(struct drm_rect *r,
>  			 int width, int height,
>  			 unsigned int rotation);
>  
> +/**
> + * drm_clip_rect_width - determine the clip rectangle width
> + * @r: clip rectangle whose width is returned
> + *
> + * RETURNS:
> + * The width of the clip rectangle.
> + */
> +static inline int drm_clip_rect_width(const struct drm_clip_rect *r)
> +{
> +	return r->x2 - r->x1;
> +}
> +
> +/**
> + * drm_clip_rect_height - determine the clip rectangle height
> + * @r: clip rectangle whose height is returned
> + *
> + * RETURNS:
> + * The height of the clip rectangle.
> + */
> +static inline int drm_clip_rect_height(const struct drm_clip_rect *r)
> +{
> +	return r->y2 - r->y1;
> +}
> +
> +/**
> + * drm_clip_rect_visible - determine if the the clip rectangle is visible
> + * @r: clip rectangle whose visibility is returned
> + *
> + * RETURNS:
> + * %true if the clip rectangle is visible, %false otherwise.
> + */
> +static inline bool drm_clip_rect_visible(const struct drm_clip_rect *r)
> +{
> +	return drm_clip_rect_width(r) > 0 && drm_clip_rect_height(r) > 0;
> +}
> +
> +/**
> + * drm_clip_rect_reset - Reset clip rectangle
> + * @clip: clip rectangle
> + *
> + * Sets clip rectangle to {0,0,0,0}.
> + */
> +static inline void drm_clip_rect_reset(struct drm_clip_rect *clip)
> +{
> +	clip->x1 = 0;
> +	clip->x2 = 0;
> +	clip->y1 = 0;
> +	clip->y2 = 0;
> +}
> +
> +/**
> + * drm_clip_rect_is_empty - Is clip rectangle empty?
> + * @clip: clip rectangle
> + *
> + * Returns true if clip rectangle is {0,0,0,0}.
> + */
> +static inline bool drm_clip_rect_is_empty(struct drm_clip_rect *clip)

Not sure this is a great name. At least for me empty means x1 == x2 && y1
== y2, which would be more generic than your test here. So either switch
the testcase (imo preferred), or rename it to something like _is_zero?

I checked the math, and besides this naming bikeshed it all looks good. So
with that addressed Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> +{
> +	return (!clip->x1 && !clip->x2 && !clip->y1 && !clip->y2);
> +}
> +
> +bool drm_clip_rect_intersect(struct drm_clip_rect *r1,
> +			     const struct drm_clip_rect *r2);
> +void drm_clip_rect_merge(struct drm_clip_rect *dst,
> +			 struct drm_clip_rect *src, unsigned num_clips,
> +			 unsigned flags, u32 width, u32 height);
> +
>  #endif
> -- 
> 2.2.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch