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drm_rect.c revision 1.3
      1 /*	$NetBSD: drm_rect.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 2011-2013 Intel Corporation
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice (including the next
     14  * paragraph) shall be included in all copies or substantial portions of the
     15  * Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     23  * SOFTWARE.
     24  */
     25 
     26 #include <sys/cdefs.h>
     27 __KERNEL_RCSID(0, "$NetBSD: drm_rect.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $");
     28 
     29 #include <linux/errno.h>
     30 #include <linux/export.h>
     31 #include <linux/kernel.h>
     32 
     33 #include <drm/drm_mode.h>
     34 #include <drm/drm_print.h>
     35 #include <drm/drm_rect.h>
     36 
     37 /**
     38  * drm_rect_intersect - intersect two rectangles
     39  * @r1: first rectangle
     40  * @r2: second rectangle
     41  *
     42  * Calculate the intersection of rectangles @r1 and @r2.
     43  * @r1 will be overwritten with the intersection.
     44  *
     45  * RETURNS:
     46  * %true if rectangle @r1 is still visible after the operation,
     47  * %false otherwise.
     48  */
     49 bool drm_rect_intersect(struct drm_rect *r1, const struct drm_rect *r2)
     50 {
     51 	r1->x1 = max(r1->x1, r2->x1);
     52 	r1->y1 = max(r1->y1, r2->y1);
     53 	r1->x2 = min(r1->x2, r2->x2);
     54 	r1->y2 = min(r1->y2, r2->y2);
     55 
     56 	return drm_rect_visible(r1);
     57 }
     58 EXPORT_SYMBOL(drm_rect_intersect);
     59 
     60 static u32 clip_scaled(int src, int dst, int *clip)
     61 {
     62 	u64 tmp;
     63 
     64 	if (dst == 0)
     65 		return 0;
     66 
     67 	/* Only clip what we have. Keeps the result bounded. */
     68 	*clip = min(*clip, dst);
     69 
     70 	tmp = mul_u32_u32(src, dst - *clip);
     71 
     72 	/*
     73 	 * Round toward 1.0 when clipping so that we don't accidentally
     74 	 * change upscaling to downscaling or vice versa.
     75 	 */
     76 	if (src < (dst << 16))
     77 		return DIV_ROUND_UP_ULL(tmp, dst);
     78 	else
     79 		return DIV_ROUND_DOWN_ULL(tmp, dst);
     80 }
     81 
     82 /**
     83  * drm_rect_clip_scaled - perform a scaled clip operation
     84  * @src: source window rectangle
     85  * @dst: destination window rectangle
     86  * @clip: clip rectangle
     87  *
     88  * Clip rectangle @dst by rectangle @clip. Clip rectangle @src by the
     89  * the corresponding amounts, retaining the vertical and horizontal scaling
     90  * factors from @src to @dst.
     91  *
     92  * RETURNS:
     93  *
     94  * %true if rectangle @dst is still visible after being clipped,
     95  * %false otherwise.
     96  */
     97 bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
     98 			  const struct drm_rect *clip)
     99 {
    100 	int diff;
    101 
    102 	diff = clip->x1 - dst->x1;
    103 	if (diff > 0) {
    104 		u32 new_src_w = clip_scaled(drm_rect_width(src),
    105 					    drm_rect_width(dst), &diff);
    106 
    107 		src->x1 = src->x2 - new_src_w;
    108 		dst->x1 += diff;
    109 	}
    110 	diff = clip->y1 - dst->y1;
    111 	if (diff > 0) {
    112 		u32 new_src_h = clip_scaled(drm_rect_height(src),
    113 					    drm_rect_height(dst), &diff);
    114 
    115 		src->y1 = src->y2 - new_src_h;
    116 		dst->y1 += diff;
    117 	}
    118 	diff = dst->x2 - clip->x2;
    119 	if (diff > 0) {
    120 		u32 new_src_w = clip_scaled(drm_rect_width(src),
    121 					    drm_rect_width(dst), &diff);
    122 
    123 		src->x2 = src->x1 + new_src_w;
    124 		dst->x2 -= diff;
    125 	}
    126 	diff = dst->y2 - clip->y2;
    127 	if (diff > 0) {
    128 		u32 new_src_h = clip_scaled(drm_rect_height(src),
    129 					    drm_rect_height(dst), &diff);
    130 
    131 		src->y2 = src->y1 + new_src_h;
    132 		dst->y2 -= diff;
    133 	}
    134 
    135 	return drm_rect_visible(dst);
    136 }
    137 EXPORT_SYMBOL(drm_rect_clip_scaled);
    138 
    139 static int drm_calc_scale(int src, int dst)
    140 {
    141 	int scale = 0;
    142 
    143 	if (WARN_ON(src < 0 || dst < 0))
    144 		return -EINVAL;
    145 
    146 	if (dst == 0)
    147 		return 0;
    148 
    149 	if (src > (dst << 16))
    150 		return DIV_ROUND_UP(src, dst);
    151 	else
    152 		scale = src / dst;
    153 
    154 	return scale;
    155 }
    156 
    157 /**
    158  * drm_rect_calc_hscale - calculate the horizontal scaling factor
    159  * @src: source window rectangle
    160  * @dst: destination window rectangle
    161  * @min_hscale: minimum allowed horizontal scaling factor
    162  * @max_hscale: maximum allowed horizontal scaling factor
    163  *
    164  * Calculate the horizontal scaling factor as
    165  * (@src width) / (@dst width).
    166  *
    167  * If the scale is below 1 << 16, round down. If the scale is above
    168  * 1 << 16, round up. This will calculate the scale with the most
    169  * pessimistic limit calculation.
    170  *
    171  * RETURNS:
    172  * The horizontal scaling factor, or errno of out of limits.
    173  */
    174 int drm_rect_calc_hscale(const struct drm_rect *src,
    175 			 const struct drm_rect *dst,
    176 			 int min_hscale, int max_hscale)
    177 {
    178 	int src_w = drm_rect_width(src);
    179 	int dst_w = drm_rect_width(dst);
    180 	int hscale = drm_calc_scale(src_w, dst_w);
    181 
    182 	if (hscale < 0 || dst_w == 0)
    183 		return hscale;
    184 
    185 	if (hscale < min_hscale || hscale > max_hscale)
    186 		return -ERANGE;
    187 
    188 	return hscale;
    189 }
    190 EXPORT_SYMBOL(drm_rect_calc_hscale);
    191 
    192 /**
    193  * drm_rect_calc_vscale - calculate the vertical scaling factor
    194  * @src: source window rectangle
    195  * @dst: destination window rectangle
    196  * @min_vscale: minimum allowed vertical scaling factor
    197  * @max_vscale: maximum allowed vertical scaling factor
    198  *
    199  * Calculate the vertical scaling factor as
    200  * (@src height) / (@dst height).
    201  *
    202  * If the scale is below 1 << 16, round down. If the scale is above
    203  * 1 << 16, round up. This will calculate the scale with the most
    204  * pessimistic limit calculation.
    205  *
    206  * RETURNS:
    207  * The vertical scaling factor, or errno of out of limits.
    208  */
    209 int drm_rect_calc_vscale(const struct drm_rect *src,
    210 			 const struct drm_rect *dst,
    211 			 int min_vscale, int max_vscale)
    212 {
    213 	int src_h = drm_rect_height(src);
    214 	int dst_h = drm_rect_height(dst);
    215 	int vscale = drm_calc_scale(src_h, dst_h);
    216 
    217 	if (vscale < 0 || dst_h == 0)
    218 		return vscale;
    219 
    220 	if (vscale < min_vscale || vscale > max_vscale)
    221 		return -ERANGE;
    222 
    223 	return vscale;
    224 }
    225 EXPORT_SYMBOL(drm_rect_calc_vscale);
    226 
    227 /**
    228  * drm_rect_debug_print - print the rectangle information
    229  * @prefix: prefix string
    230  * @r: rectangle to print
    231  * @fixed_point: rectangle is in 16.16 fixed point format
    232  */
    233 void drm_rect_debug_print(const char *prefix, const struct drm_rect *r, bool fixed_point)
    234 {
    235 	if (fixed_point)
    236 		DRM_DEBUG_KMS("%s" DRM_RECT_FP_FMT "\n", prefix, DRM_RECT_FP_ARG(r));
    237 	else
    238 		DRM_DEBUG_KMS("%s" DRM_RECT_FMT "\n", prefix, DRM_RECT_ARG(r));
    239 }
    240 EXPORT_SYMBOL(drm_rect_debug_print);
    241 
    242 /**
    243  * drm_rect_rotate - Rotate the rectangle
    244  * @r: rectangle to be rotated
    245  * @width: Width of the coordinate space
    246  * @height: Height of the coordinate space
    247  * @rotation: Transformation to be applied
    248  *
    249  * Apply @rotation to the coordinates of rectangle @r.
    250  *
    251  * @width and @height combined with @rotation define
    252  * the location of the new origin.
    253  *
    254  * @width correcsponds to the horizontal and @height
    255  * to the vertical axis of the untransformed coordinate
    256  * space.
    257  */
    258 void drm_rect_rotate(struct drm_rect *r,
    259 		     int width, int height,
    260 		     unsigned int rotation)
    261 {
    262 	struct drm_rect tmp;
    263 
    264 	if (rotation & (DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y)) {
    265 		tmp = *r;
    266 
    267 		if (rotation & DRM_MODE_REFLECT_X) {
    268 			r->x1 = width - tmp.x2;
    269 			r->x2 = width - tmp.x1;
    270 		}
    271 
    272 		if (rotation & DRM_MODE_REFLECT_Y) {
    273 			r->y1 = height - tmp.y2;
    274 			r->y2 = height - tmp.y1;
    275 		}
    276 	}
    277 
    278 	switch (rotation & DRM_MODE_ROTATE_MASK) {
    279 	case DRM_MODE_ROTATE_0:
    280 		break;
    281 	case DRM_MODE_ROTATE_90:
    282 		tmp = *r;
    283 		r->x1 = tmp.y1;
    284 		r->x2 = tmp.y2;
    285 		r->y1 = width - tmp.x2;
    286 		r->y2 = width - tmp.x1;
    287 		break;
    288 	case DRM_MODE_ROTATE_180:
    289 		tmp = *r;
    290 		r->x1 = width - tmp.x2;
    291 		r->x2 = width - tmp.x1;
    292 		r->y1 = height - tmp.y2;
    293 		r->y2 = height - tmp.y1;
    294 		break;
    295 	case DRM_MODE_ROTATE_270:
    296 		tmp = *r;
    297 		r->x1 = height - tmp.y2;
    298 		r->x2 = height - tmp.y1;
    299 		r->y1 = tmp.x1;
    300 		r->y2 = tmp.x2;
    301 		break;
    302 	default:
    303 		break;
    304 	}
    305 }
    306 EXPORT_SYMBOL(drm_rect_rotate);
    307 
    308 /**
    309  * drm_rect_rotate_inv - Inverse rotate the rectangle
    310  * @r: rectangle to be rotated
    311  * @width: Width of the coordinate space
    312  * @height: Height of the coordinate space
    313  * @rotation: Transformation whose inverse is to be applied
    314  *
    315  * Apply the inverse of @rotation to the coordinates
    316  * of rectangle @r.
    317  *
    318  * @width and @height combined with @rotation define
    319  * the location of the new origin.
    320  *
    321  * @width correcsponds to the horizontal and @height
    322  * to the vertical axis of the original untransformed
    323  * coordinate space, so that you never have to flip
    324  * them when doing a rotatation and its inverse.
    325  * That is, if you do ::
    326  *
    327  *     drm_rect_rotate(&r, width, height, rotation);
    328  *     drm_rect_rotate_inv(&r, width, height, rotation);
    329  *
    330  * you will always get back the original rectangle.
    331  */
    332 void drm_rect_rotate_inv(struct drm_rect *r,
    333 			 int width, int height,
    334 			 unsigned int rotation)
    335 {
    336 	struct drm_rect tmp;
    337 
    338 	switch (rotation & DRM_MODE_ROTATE_MASK) {
    339 	case DRM_MODE_ROTATE_0:
    340 		break;
    341 	case DRM_MODE_ROTATE_90:
    342 		tmp = *r;
    343 		r->x1 = width - tmp.y2;
    344 		r->x2 = width - tmp.y1;
    345 		r->y1 = tmp.x1;
    346 		r->y2 = tmp.x2;
    347 		break;
    348 	case DRM_MODE_ROTATE_180:
    349 		tmp = *r;
    350 		r->x1 = width - tmp.x2;
    351 		r->x2 = width - tmp.x1;
    352 		r->y1 = height - tmp.y2;
    353 		r->y2 = height - tmp.y1;
    354 		break;
    355 	case DRM_MODE_ROTATE_270:
    356 		tmp = *r;
    357 		r->x1 = tmp.y1;
    358 		r->x2 = tmp.y2;
    359 		r->y1 = height - tmp.x2;
    360 		r->y2 = height - tmp.x1;
    361 		break;
    362 	default:
    363 		break;
    364 	}
    365 
    366 	if (rotation & (DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y)) {
    367 		tmp = *r;
    368 
    369 		if (rotation & DRM_MODE_REFLECT_X) {
    370 			r->x1 = width - tmp.x2;
    371 			r->x2 = width - tmp.x1;
    372 		}
    373 
    374 		if (rotation & DRM_MODE_REFLECT_Y) {
    375 			r->y1 = height - tmp.y2;
    376 			r->y2 = height - tmp.y1;
    377 		}
    378 	}
    379 }
    380 EXPORT_SYMBOL(drm_rect_rotate_inv);
    381