From: Ville Syrjälä ville.syrjala@linux.intel.com
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_crtc.c | 102 ++++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_crtc.h | 4 ++ 2 files changed, 106 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index f64e572..8918179 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -4078,3 +4078,105 @@ bool drm_region_clip_scaled(struct drm_region *src, struct drm_region *dst, return drm_region_clip(dst, clip); } EXPORT_SYMBOL(drm_region_clip_scaled); + +/** + * drm_calc_hscale - calculate the horizontal scaling factor + * @src: source window region + * @dst: destination window region + * @min_hscale: minimum allowed horizontal scaling factor + * @max_hscale: maximum allowed horizontal scaling factor + * + * Calculate the horizontal scaling factor as + * (@src width) / (@dst width). + * + * If the calculated scaling factor is below @min_hscale, + * decrease the width of region @dst to compensate. + * + * If the calculcated scaling factor is above @max_hscale, + * decrease the width of region @src to compensate. + * + * RETURNS: + * The horizontal scaling factor. + */ +int drm_calc_hscale(struct drm_region *src, struct drm_region *dst, + int min_hscale, int max_hscale) +{ + int src_w = drm_region_width(src); + int dst_w = drm_region_width(dst); + int hscale; + + if (dst_w <= 0) + return 0; + + hscale = src_w / dst_w; + + if (hscale < min_hscale) { + int max_dst_w = src_w / min_hscale; + + drm_region_adjust_size(dst, max_dst_w - dst_w, 0); + + return min_hscale; + } + + if (hscale > max_hscale) { + int max_src_w = dst_w * max_hscale; + + drm_region_adjust_size(src, max_src_w - src_w, 0); + + return max_hscale; + } + + return hscale; +} +EXPORT_SYMBOL(drm_calc_hscale); + +/** + * drm_calc_vscale - calculate the vertical scaling factor + * @src: source window region + * @dst: destination window region + * @min_vscale: minimum allowed vertical scaling factor + * @max_vscale: maximum allowed vertical scaling factor + * + * Calculate the vertical scaling factor as + * (@src height) / (@dst height). + * + * If the calculated scaling factor is below @min_vscale, + * decrease the height of region @dst to compensate. + * + * If the calculcated scaling factor is above @max_vscale, + * decrease the height of region @src to compensate. + * + * RETURNS: + * The vertical scaling factor. + */ +int drm_calc_vscale(struct drm_region *src, struct drm_region *dst, + int min_vscale, int max_vscale) +{ + int src_h = drm_region_height(src); + int dst_h = drm_region_height(dst); + int vscale; + + if (dst_h <= 0) + return 0; + + vscale = src_h / dst_h; + + if (vscale < min_vscale) { + int max_dst_h = src_h / min_vscale; + + drm_region_adjust_size(dst, 0, max_dst_h - dst_h); + + return min_vscale; + } + + if (vscale > max_vscale) { + int max_src_h = dst_h * max_vscale; + + drm_region_adjust_size(src, 0, max_src_h - src_h); + + return max_vscale; + } + + return vscale; +} +EXPORT_SYMBOL(drm_calc_vscale); diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 0ac6d83..a80a346 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1105,5 +1105,9 @@ extern bool drm_region_clip_scaled(struct drm_region *src, struct drm_region *dst, const struct drm_region *clip, int hscale, int vscale); +extern int drm_calc_hscale(struct drm_region *src, struct drm_region *dst, + int min_hscale, int max_hscale); +extern int drm_calc_vscale(struct drm_region *src, struct drm_region *dst, + int min_vscale, int max_vscale);
#endif /* __DRM_CRTC_H__ */