[vlc-devel] [PATCH] Cursor integration on X11 video screenshots thanks to xfixes

[Mehdi Lauters]

---
 modules/access/screen/xcb.c |  116 ++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 115 insertions(+), 1 deletions(-)

diff --git a/modules/access/screen/xcb.c b/modules/access/screen/xcb.c
index c31d380..2fa750b 100644
--- a/modules/access/screen/xcb.c
+++ b/modules/access/screen/xcb.c
@@ -402,7 +402,6 @@ discard:
     /* Capture screen */
     xcb_drawable_t drawable =
         (sys->window != geo->root) ? sys->pixmap : sys->window;
-    free (geo);
 
     xcb_get_image_reply_t *img;
     img = xcb_get_image_reply (conn,
@@ -411,6 +410,121 @@ discard:
     if (img == NULL)
         return;
 
+    xcb_generic_error_t     xcbError;
+
+    // initializing xfixes (to get the cursor image)
+    xcb_xfixes_query_version_reply(conn,
+            xcb_xfixes_query_version(conn,XCB_XFIXES_MAJOR_VERSION,
+                    XCB_XFIXES_MINOR_VERSION),
+            NULL);
+
+    // we ask for pointer informations ( on the same screen or not )
+    xcb_query_pointer_cookie_t pointerCookie = xcb_query_pointer(conn, drawable);
+    xcb_query_pointer_reply_t * pointerReply = xcb_query_pointer_reply (conn,
+            pointerCookie, &xcbError);
+
+
+    if(xcbError.error_code!=0)
+    {
+        msg_Warn (demux, "unable to locate cursor");
+    }
+    else
+    {
+        // if the cursor is on the same screen
+        if(pointerReply->same_screen == 1)
+        {
+            // we get more information about the cursor
+            xcb_xfixes_get_cursor_image_cookie_t cursorCookie = xcb_xfixes_get_cursor_image(conn);
+            xcb_xfixes_get_cursor_image_reply_t* cursorImgReply = xcb_xfixes_get_cursor_image_reply (conn, cursorCookie, &xcbError);
+
+            if(xcbError.error_code==0)
+            {
+                // indices to browse images
+                int iScreen;
+                int iPointer=0;
+
+                // images data
+                uint8_t *screenImageData=NULL;
+                uint8_t *pointerImageData;
+
+                // we get the cursor image data
+                pointerImageData = xcb_xfixes_get_cursor_image_cursor_image(cursorImgReply);
+
+                // we get screen image data
+                screenImageData = xcb_get_image_data (img);
+
+
+                //indices to browse the pointer picture
+                int ixCursor=0,
+                    iyCursor=0;
+                // top left corner of the pointer picture on the screen picture
+                int xMinScreen=cursorImgReply->x-cursorImgReply->xhot,
+                // top right corner of the pointer picture on the screen picture
+                    yMinScreen=cursorImgReply->y-cursorImgReply->yhot,
+                // bottom left corner of the pointer picture on the screen picture
+                    xMaxScreen=cursorImgReply->x+(cursorImgReply->width-cursorImgReply->xhot),
+                // bottom right corner of the pointer picture on the screen picture
+                    yMaxScreen=cursorImgReply->y+(cursorImgReply->width-cursorImgReply->yhot);
+
+
+                // be sure that the entire pointer is on the screenshot
+                if(!(xMinScreen<0 || yMinScreen <0 || xMaxScreen > geo->width
+                        || yMaxScreen > geo->height))
+                {
+
+                    // we browse the screen picture
+                    for(int ix=xMinScreen; // to center on the right point
+                            ix<xMaxScreen;
+                            ix++)
+                    {
+                        iyCursor=0;
+                        for(int iy=yMinScreen; // to center on the right point
+                                iy<yMaxScreen;
+                                iy++)
+                        {
+                            //get the indice of the (ix,iy) pixel in the screen data buffer
+                            iScreen=iy*geo->width+ix;
+
+
+    //                      //get the relative indice of the cursor
+                            iPointer=iyCursor*cursorImgReply->width+ixCursor;
+
+                            // get the indice of the first color of the current pixel
+                            iScreen=iScreen*4;
+                            iPointer=iPointer*4;
+
+                            // /!\ no transparency
+                            if(((uint8_t *)pointerImageData)[iPointer+3]>100)
+                            {
+                                // copying pixels colors
+                                // r
+                                screenImageData[iScreen]=pointerImageData[iPointer];
+                                // g
+                                screenImageData[iScreen+1]=pointerImageData[iPointer+1];
+                                // b
+                                screenImageData[iScreen+2]=pointerImageData[iPointer+2];
+                            }
+                            iyCursor++;
+                        }
+                        ixCursor++;
+                    }
+                }
+                else
+                {
+                    msg_Warn (demux, "Cursor not on the picture");
+                }
+                free(cursorImgReply);
+            }
+            else
+            {
+                msg_Warn (demux, "unable to find cursor image");
+            }
+        }
+    }
+
+    free(pointerReply);
+    free (geo);
+
     uint8_t *data = xcb_get_image_data (img);
     size_t datalen = xcb_get_image_data_length (img);
     block_t *block = block_heap_Alloc (img, data + datalen - (uint8_t *)img);
-- 
1.7.1