Class: WinGdi32Ruby::Gdi32

Inherits:
Object
  • Object
show all
Defined in:
lib/win-gdi32-ruby.rb

Class Method Summary collapse

Class Method Details

.capture(left, top, right, bottom) ⇒ Object

Captures the window as a bitmap

left, top. right, bottom

specifies the rectangle to capture

Returns

a bitmap handle



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# File 'lib/win-gdi32-ruby.rb', line 65

def Gdi32.capture(left, top, right, bottom)
  # create a DC for the screen and a memory DC compatible to screen DC
  hscr_dc = Gdi32.create_dc
  hmem_dc = Gdi32.create_compatible_dc(hscr_dc)

  width = right - left
  height = bottom - top

  # create a bitmap compatible with the screen DC
  hbitmap = Gdi32.create_compatible_bitmap(hscr_dc, width, height)

  # select new bitmap into memory DC
  holdbitmap =   Gdi32.select_object(hmem_dc, hbitmap)
  
  # bitblt screen DC to memory DC
  Gdi32.bit_blt(hscr_dc, left, top, width, height, hmem_dc)
  
  # select old bitmap back into memory DC and get handle to bitmap of the screen
  hbitmap = Gdi32.select_object(hmem_dc, holdbitmap);

  # clean up
  Gdi32.delete_dc(hscr_dc);
  Gdi32.delete_dc(hmem_dc);
  
  # return handle to the bitmap
  hbitmap
end

.load_bitmap(filename) ⇒ Object

Loads a bitmap from a BMP file

filename

name of file to load

Returns

an array containing a handle to the bitmap and a handle to the palette

<tt>[hbitmap, hpalette]</tt>



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# File 'lib/win-gdi32-ruby.rb', line 51

def Gdi32.load_bitmap(filename)
  sb = bitmap_helper 'OpenBitmap', 'SP', 'I'

  # Prepare array for return values
  bm_plt = [0, 0].pack('L*')
  raise "Failed to load '#{filename}'" unless sb.call(filename, bm_plt )
  hbitmap, hpalette = bm_plt.unpack('L*')

  [hbitmap, hpalette]
end

.save_bitmap(hbitmap, filename) ⇒ Object

Save the specified bitmap to a file

hwnd

Handle to the main window (used to get the system pallete)

hbitmap

Handle to the bitmap to save

filename

Filename for the bitmap

Returns

Void



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# File 'lib/win-gdi32-ruby.rb', line 38

def Gdi32.save_bitmap(hbitmap, filename)
  # Used to get palette
  hwnd = hbitmap

  sb = bitmap_helper 'SaveBitmap', 'LLS', 'V'

  sb.call hwnd, hbitmap, filename
end