/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2012  Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
using System;
using System.Drawing;
using System.Runtime.InteropServices;

namespace GreenshotPlugin.UnmanagedHelpers {
	public static class GDIExtensions {
		public static bool AreRectangleCornersVisisble(this Region region, Rectangle rectangle) {
			Point topLeft = new Point(rectangle.X, rectangle.Y);
			Point topRight = new Point(rectangle.X + rectangle.Width, rectangle.Y);
			Point bottomLeft = new Point(rectangle.X, rectangle.Y + rectangle.Height);
			Point bottomRight = new Point(rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height);
			bool topLeftVisible = region.IsVisible(topLeft);
			bool topRightVisible = region.IsVisible(topRight);
			bool bottomLeftVisible = region.IsVisible(bottomLeft);
			bool bottomRightVisible = region.IsVisible(bottomRight);

			return topLeftVisible && topRightVisible && bottomLeftVisible && bottomRightVisible;
		}
	}
	/// <summary>
	/// GDI32 Helpers
	/// </summary>
	public static class GDI32 {
		[DllImport("gdi32", SetLastError=true)]
		public static extern bool BitBlt(IntPtr hObject,int nXDest,int nYDest, int nWidth,int nHeight,IntPtr hObjectSource, int nXSrc,int nYSrc, CopyPixelOperation dwRop);
		[DllImport("gdi32", SetLastError=true)]
		public static extern bool StretchBlt(IntPtr hdcDest, int nXOriginDest, int nYOriginDest, int nWidthDest, int nHeightDest, IntPtr hdcSrc, int nXOriginSrc, int nYOriginSrc, int nWidthSrc, int nHeightSrc, CopyPixelOperation dwRop );
		[DllImport("gdi32", SetLastError=true)]
		public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
		[DllImport("gdi32", SetLastError=true)]
		public static extern bool DeleteDC(IntPtr hDC);
		[DllImport("gdi32", SetLastError=true)]
		public static extern bool DeleteObject(IntPtr hObject);
		[DllImport("gdi32", SetLastError=true)]
		public static extern IntPtr SelectObject(IntPtr hDC,IntPtr hObject);
		[DllImport("gdi32", SetLastError=true)]
		public static extern IntPtr CreateDIBSection(IntPtr hdc, ref BitmapInfoHeader bmi, uint Usage, out IntPtr bits, IntPtr hSection, uint dwOffset); 
		[DllImport("gdi32", SetLastError=true)]
		public static extern IntPtr CreateRectRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect);
		[DllImport("gdi32", SetLastError=true)]
		public static extern int GetClipBox(IntPtr hdc, out RECT lprc);
		[DllImport("gdi32", SetLastError = true)]
		public static extern uint GetPixel(IntPtr hdc, int nXPos, int nYPos);
		[DllImport("gdi32", SetLastError = true)]
		public static extern IntPtr CreateRoundRectRgn(int x1, int y1, int x2, int y2, int cx, int cy);
		[DllImport("gdi32", SetLastError = true)]
		public static extern int GetDeviceCaps(IntPtr hdc, DeviceCaps nIndex);
		
		/// <summary>
		/// Doesn't work?
		/// </summary>
		/// <param name="target"></param>
		/// <param name="source"></param>
		public static void StretchBlt(this Graphics target, Bitmap sourceBitmap, Rectangle source, Rectangle destination) {
			IntPtr hDCSrc = IntPtr.Zero;
			IntPtr hDCDest = IntPtr.Zero;
			try {
				hDCDest = target.GetHdc();
				hDCSrc = CreateCompatibleDC(hDCDest);
				IntPtr pOrig = SelectObject(hDCSrc, sourceBitmap.GetHbitmap());
				StretchBlt(hDCDest, destination.X, destination.Y, destination.Width, destination.Height, hDCSrc, source.Left, source.Top, source.Width, source.Height, CopyPixelOperation.SourceCopy);				
				IntPtr pNew = SelectObject(hDCDest, pOrig);
			} finally {
				if (hDCSrc != IntPtr.Zero) {
					DeleteDC(hDCSrc);
				}
				if (hDCDest != IntPtr.Zero) {
					target.ReleaseHdc(hDCDest);
				}
			}
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="target"></param>
		/// <param name="source"></param>
		public static void BitBlt(this Graphics target, Bitmap sourceBitmap, Rectangle source, Point destination) {
			IntPtr hDCSrc = IntPtr.Zero;
			IntPtr hDCDest = IntPtr.Zero;
			try {
				hDCDest = target.GetHdc();
				hDCSrc = CreateCompatibleDC(hDCDest);
				IntPtr pOrig = SelectObject(hDCSrc, sourceBitmap.GetHbitmap());
				BitBlt(hDCDest, destination.X, destination.Y, source.Width, source.Height, hDCSrc, source.Left, source.Top, CopyPixelOperation.SourceCopy);
				IntPtr pNew = SelectObject(hDCDest, pOrig);
			} finally {
				if (hDCSrc != IntPtr.Zero) {
					DeleteDC(hDCSrc);
				}
				if (hDCDest != IntPtr.Zero) {
					target.ReleaseHdc(hDCDest);
				}
			}
		}
	}

	[StructLayout(LayoutKind.Sequential, Pack = 2)]
	public struct BitmapFileHeader {
		public static readonly short BM = 0x4d42; // BM
		public short bfType;
		public int bfSize;
		public short bfReserved1;
		public short bfReserved2;
		public int bfOffBits;
	}

	[StructLayout(LayoutKind.Sequential)] 
	public struct BitmapInfoHeader {
		public uint biSize;
		public int biWidth;
		public int biHeight;
		public short biPlanes;
		public short biBitCount;
		public uint biCompression;
		public uint biSizeImage;
		public int biXPelsPerMeter;
		public int biYPelsPerMeter;
		public uint biClrUsed;
		public int biClrImportant;

		private const int BI_RGB = 0;	//Das Bitmap ist nicht komprimiert
		private const int BI_RLE8 = 1; //Das Bitmap ist komprimiert (Für 8-Bit Bitmaps)
		private const int BI_RLE4 = 2; //Das Bitmap ist komprimiert (Für 4-Bit Bitmaps)
		private const int BI_BITFIELDS = 3; //Das Bitmap ist nicht komprimiert. Die Farbtabelle enthält 
		public const int DIB_RGB_COLORS = 0;

		public BitmapInfoHeader(int width, int height, short bpp) {
			biSize = (uint)Marshal.SizeOf(typeof(BitmapInfoHeader));	// BITMAPINFOHEADER is 40 bytes
			biPlanes = 1;	// Should allways be 1
			biCompression = BI_RGB;
			biWidth=width;
			biHeight=height;
			biBitCount=bpp;
			biSizeImage = 0;
			biXPelsPerMeter = 0;
			biYPelsPerMeter = 0;
			biClrUsed = 0;
			biClrImportant = 0;
		}
	}
}