[xscreensaver] / OSX / osxgrabscreen.m

/* xscreensaver, Copyright (c) 1992-2006 Jamie Zawinski <jwz@jwz.org>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation.  No representations are made about the suitability of this
 * software for any purpose.  It is provided "as is" without express or 
 * implied warranty.
 */

/* This is the OSX implementation of desktop-grabbing and image-loading.
 */

#import <stdlib.h>
#import <Cocoa/Cocoa.h>
#import "jwxyz.h"
#import "grabscreen.h"
#import "colorbars.h"
#import "resources.h"
#import "usleep.h"


static void
copy_framebuffer_to_ximage (CGDirectDisplayID cgdpy, XImage *xim,
                            int window_x, int window_y)
{
  unsigned char *data = (unsigned char *) 
    CGDisplayAddressForPosition (cgdpy, window_x, window_y);
  int bpp = CGDisplayBitsPerPixel (cgdpy);
  int spp = CGDisplaySamplesPerPixel (cgdpy);
  int bps = CGDisplayBitsPerSample (cgdpy);
  int bpr = CGDisplayBytesPerRow (cgdpy);

  int y;
  int ximw = xim->width;
  int ximh = xim->height;

  unsigned long *odata = (unsigned long *) xim->data;

  switch (bpp) {
  case 32:
    if (spp != 3) abort();
    if (bps != 8) abort();
    int xwpl = xim->bytes_per_line/4;
    for (y = 0; y < ximh; y++) {
      // We can do this because the frame buffer and XImage are both ARGB 32.
      // Both PPC and Intel use ARGB, viewed in word order (not byte-order).
      memcpy (odata, data, ximw * 4);
      odata += xwpl;
      data += bpr;
    }
    break;

  case 16:
    if (spp != 3) abort();
    if (bps != 5) abort();
    for (y = 0; y < ximh; y++) {
      unsigned short *ip = (unsigned short *) data;
      int x;
      for (x = 0; x < ximw; x++) {
        unsigned short p = *ip++;
        // This should be ok on both PPC and Intel (ARGB, word order)
        unsigned char r = (p >> 10) & 0x1F;
        unsigned char g = (p >>  5) & 0x1F;
        unsigned char b = (p      ) & 0x1F;
        r = (r << 3) | (r >> 2);
        g = (g << 3) | (g >> 2);
        b = (b << 3) | (b >> 2);
        unsigned long pixel = 0xFF000000 | (r << 16) | (g << 8) | b;
        // XPutPixel (xim, x, y, pixel);
        *odata++ = pixel;
      }
      data += bpr;
    }
    break;

  case 8:
    {
      /* Get the current palette of the display. */
      CGDirectPaletteRef pal = CGPaletteCreateWithDisplay (cgdpy);

      /* Map it to 32bpp pixels */
      unsigned long map[256];
      for (y = 0; y < 256; y++) {
        CGDeviceColor c = CGPaletteGetColorAtIndex (pal, y);
        unsigned char r = c.red   * 255.0;
        unsigned char g = c.green * 255.0;
        unsigned char b = c.blue  * 255.0;
        unsigned long pixel = 0xFF000000 | (r << 16) | (g << 8) | b;
        map[y] = pixel;
      }

      for (y = 0; y < ximh; y++) {
        unsigned char *ip = data;
        int x;
        for (x = 0; x < ximw; x++) {
          *odata++ = map[*ip++];
        }
        data += bpr;
      }
      CGPaletteRelease (pal);
    }
    break;

  default:
    abort();
    break;
  }
}


/* Loads an image into the Drawable, returning once the image is loaded.
 */
void
osx_grab_desktop_image (Screen *screen, Window xwindow, Drawable drawable)
{
  Display *dpy = DisplayOfScreen (screen);
  XWindowAttributes xgwa;
  NSView *nsview = jwxyz_window_view (xwindow);
  NSWindow *nswindow = [nsview window];
  int window_x, window_y;
  Window unused;

  // figure out where this window is on the screen
  //
  XGetWindowAttributes (dpy, xwindow, &xgwa);
  XTranslateCoordinates (dpy, xwindow, RootWindowOfScreen (screen), 0, 0, 
                         &window_x, &window_y, &unused);
  
  // Use the size of the Drawable, not the Window.
  {
    Window r;
    int x, y;
    unsigned int w, h, bbw, d;
    XGetGeometry (dpy, drawable, &r, &x, &y, &w, &h, &bbw, &d);
    xgwa.width = w;
    xgwa.height = h;
  }

  // Create a tmp ximage to hold the screen data.
  //
  XImage *xim = XCreateImage (dpy, xgwa.visual, 32, ZPixmap, 0, 0,
                              xgwa.width, xgwa.height, 8, 0);
  xim->data = (char *) malloc (xim->height * xim->bytes_per_line);


  // Find the address in the frame buffer of the top left of this window.
  //
  CGDirectDisplayID cgdpy = 0;
  {
    CGPoint p;
    // #### this isn't quite right for screen 2: it's offset slightly.
    p.x = window_x;
    p.y = window_y;
    CGDisplayCount n;
    CGGetDisplaysWithPoint (p, 1, &cgdpy, &n);
    if (!cgdpy) abort();
  }

  // Paint a transparent "hole" in this window.
  //
  BOOL oopaque = [nswindow isOpaque];
  [nswindow setOpaque:NO];

  [[NSColor clearColor] set];
  NSRectFill ([nsview frame]);
  [[nswindow graphicsContext] flushGraphics];


  // Without this, we get a dozen black scanlines at the top.
  // #### But with this, the screen saver loops, because calling this
  //      seems to implicitly mark the display as non-idle!
  // CGDisplayCaptureWithOptions (cgdpy, kCGCaptureNoFill);

  // #### So let's try waiting for the vertical blank instead...
  //      Nope, that doesn't work.
  //
  // CGDisplayWaitForBeamPositionOutsideLines (cgdpy, 0,
  //   window_y + [nswindow frame].size.height);

  // #### Ok, try a busy-wait?
  //      Nope.
  //

  // #### Ok, just fuckin' sleep!
  //
  usleep (100000);


  // Pull the bits out of the frame buffer.
  //
  copy_framebuffer_to_ximage (cgdpy, xim, window_x, window_y);

  // CGDisplayRelease (cgdpy);

  // Make the window visible again.
  //
  [nswindow setOpaque:oopaque];

  // Splat the XImage onto the target drawable (probably the window)
  // and free the bits.
  //
  GC gc = 0;
  XPutImage (dpy, drawable, gc, xim, 0, 0, 0, 0, xim->width, xim->height);
  XDestroyImage (xim);
}


/* Returns the EXIF rotation property of the image, if any.
 */
static int
exif_rotation (const char *filename)
{
  /* This is a ridiculous amount of rigamarole to go through, but for some
     reason the "Orientation" tag does not exist in the "NSImageEXIFData"
     dictionary inside the NSBitmapImageRep of the NSImage.  Several other
     EXIF tags are there (e.g., shutter speed) but not orientation.  WTF?
   */
  CFStringRef s = CFStringCreateWithCString (NULL, filename, 
                                             kCFStringEncodingUTF8);
  CFURLRef url = CFURLCreateWithFileSystemPath (NULL, s, 
                                                kCFURLPOSIXPathStyle, 0);
  CGImageSourceRef cgimg = CGImageSourceCreateWithURL (url, NULL);
  if (! cgimg) return -1;

  NSDictionary *props = (NSDictionary *)
    CGImageSourceCopyPropertiesAtIndex (cgimg, 0, NULL);
  int rot = [[props objectForKey:@"Orientation"] intValue];
  CFRelease (cgimg);
  CFRelease (url);
  CFRelease (s);
  return rot;
}


/* Loads an image file and splats it onto the drawable.
   The image is drawn as large as possible while preserving its aspect ratio.
   If geom_ret is provided, the actual rectangle the rendered image takes
   up will be returned there.
 */
Bool
osx_load_image_file (Screen *screen, Window xwindow, Drawable drawable,
                     const char *filename, XRectangle *geom_ret)
{
  NSImage *img = [[NSImage alloc] initWithContentsOfFile:
                                    [NSString stringWithCString:filename
                                              encoding:NSUTF8StringEncoding]];
  if (!img)
    return False;

  jwxyz_draw_NSImage (DisplayOfScreen (screen), drawable, img, geom_ret,
                      exif_rotation (filename));
  [img release];
  return True;
}