move intel crtc xv clipping helper to the xserver

The code is generic and can be used by any overlay-based card when
adding randr 1.2 support.  Tested on radeon.

hw/xfree86/modes/xf86Crtc.c

@@ -45,6 +45,8 @@
 #include "picturestr.h"
 #endif
 
+#include "xf86xv.h"
+
 /*
  * Initialize xf86CrtcConfig structure
  */
@@ -2144,3 +2146,119 @@ xf86ConnectorGetName(xf86ConnectorType connector)
 {
     return _xf86ConnectorNames[connector];
 }
+
+static void
+x86_crtc_box_intersect(BoxPtr dest, BoxPtr a, BoxPtr b)
+{
+    dest->x1 = a->x1 > b->x1 ? a->x1 : b->x1;
+    dest->x2 = a->x2 < b->x2 ? a->x2 : b->x2;
+    dest->y1 = a->y1 > b->y1 ? a->y1 : b->y1;
+    dest->y2 = a->y2 < b->y2 ? a->y2 : b->y2;
+
+    if (dest->x1 >= dest->x2 || dest->y1 >= dest->y2)
+	dest->x1 = dest->x2 = dest->y1 = dest->y2 = 0;
+}
+
+static void
+x86_crtc_box(xf86CrtcPtr crtc, BoxPtr crtc_box)
+{
+    if (crtc->enabled) {
+	crtc_box->x1 = crtc->x;
+	crtc_box->x2 = crtc->x + xf86ModeWidth(&crtc->mode, crtc->rotation);
+	crtc_box->y1 = crtc->y;
+	crtc_box->y2 = crtc->y + xf86ModeHeight(&crtc->mode, crtc->rotation);
+    } else
+	crtc_box->x1 = crtc_box->x2 = crtc_box->y1 = crtc_box->y2 = 0;
+}
+
+static int
+xf86_crtc_box_area(BoxPtr box)
+{
+    return (int) (box->x2 - box->x1) * (int) (box->y2 - box->y1);
+}
+
+/*
+ * Return the crtc covering 'box'. If two crtcs cover a portion of
+ * 'box', then prefer 'desired'. If 'desired' is NULL, then prefer the crtc
+ * with greater coverage
+ */
+
+static xf86CrtcPtr
+xf86_covering_crtc(ScrnInfoPtr pScrn,
+		   BoxPtr      box,
+		   xf86CrtcPtr desired,
+		   BoxPtr      crtc_box_ret)
+{
+    xf86CrtcConfigPtr   xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
+    xf86CrtcPtr		crtc, best_crtc;
+    int			coverage, best_coverage;
+    int			c;
+    BoxRec		crtc_box, cover_box;
+
+    best_crtc = NULL;
+    best_coverage = 0;
+    crtc_box_ret->x1 = 0;
+    crtc_box_ret->x2 = 0;
+    crtc_box_ret->y1 = 0;
+    crtc_box_ret->y2 = 0;
+    for (c = 0; c < xf86_config->num_crtc; c++) {
+	crtc = xf86_config->crtc[c];
+	x86_crtc_box(crtc, &crtc_box);
+	x86_crtc_box_intersect(&cover_box, &crtc_box, box);
+	coverage = xf86_crtc_box_area(&cover_box);
+	if (coverage && crtc == desired) {
+	    *crtc_box_ret = crtc_box;
+	    return crtc;
+	} else if (coverage > best_coverage) {
+	    *crtc_box_ret = crtc_box;
+	    best_crtc = crtc;
+	    best_coverage = coverage;
+	}
+    }
+    return best_crtc;
+}
+
+/*
+ * For overlay video, compute the relevant CRTC and
+ * clip video to that
+ */
+
+Bool
+xf86_crtc_clip_video_helper(ScrnInfoPtr pScrn,
+			    xf86CrtcPtr *crtc_ret,
+			    xf86CrtcPtr desired_crtc,
+			    BoxPtr      dst,
+			    INT32	*xa,
+			    INT32	*xb,
+			    INT32	*ya,
+			    INT32	*yb,
+			    RegionPtr   reg,
+			    INT32	width,
+			    INT32	height)
+{
+    Bool	ret;
+    RegionRec	crtc_region_local;
+    RegionPtr	crtc_region = reg;
+    
+    if (crtc_ret) {
+	BoxRec		crtc_box;
+	xf86CrtcPtr	crtc = xf86_covering_crtc(pScrn, dst,
+						  desired_crtc,
+						  &crtc_box);
+
+	if (crtc) {
+	    REGION_INIT (pScreen, &crtc_region_local, &crtc_box, 1);
+	    crtc_region = &crtc_region_local;
+	    REGION_INTERSECT (pScreen, crtc_region, crtc_region, reg);
+	}
+	*crtc_ret = crtc;
+    }
+
+    ret = xf86XVClipVideoHelper(dst, xa, xb, ya, yb, 
+				crtc_region, width, height);
+
+    if (crtc_region != reg)
+	REGION_UNINIT (pScreen, &crtc_region_local);
+
+    return ret;
+}

hw/xfree86/modes/xf86Crtc.h

@@ -765,5 +765,24 @@ xf86_hide_cursors (ScrnInfoPtr scrn);
  */
 void
 xf86_cursors_fini (ScreenPtr screen);
+
+/*
+ * For overlay video, compute the relevant CRTC and
+ * clip video to that.
+ * wraps xf86XVClipVideoHelper()
+ */
+
+Bool
+xf86_crtc_clip_video_helper(ScrnInfoPtr pScrn,
+			    xf86CrtcPtr *crtc_ret,
+			    xf86CrtcPtr desired_crtc,
+			    BoxPtr      dst,
+			    INT32	*xa,
+			    INT32	*xb,
+			    INT32	*ya,
+			    INT32	*yb,
+			    RegionPtr   reg,
+			    INT32	width,
+			    INT32	height);
     
 #endif /* _XF86CRTC_H_ */