//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
//
// File: TileBrush.cs
//
// Description: This file contains the implementation of TileBrush.
//              The TileBrush is an abstract class of Brushes which describes
//              a way to fill a region by tiling.  The contents of the tiles
//              are described by classes derived from TileBrush.
//
// History:
//  04/29/2003 : Microsoft - Created it.
//
//---------------------------------------------------------------------------
    
using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Security;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Composition;
using MS.Internal;
using System.Runtime.InteropServices;
 
namespace System.Windows.Media 
{
    /// <summary>
    /// TileBrush
    /// The TileBrush is an abstract class of Brushes which describes
    /// a way to fill a region by tiling.  The contents of the tiles
    /// are described by classes derived from TileBrush.
    /// </summary>
    public abstract partial class TileBrush : Brush
    {
        #region Constructors
    
        /// <summary>
        /// Protected constructor for TileBrush.  
        /// Sets all values to their defaults.  
        /// To set property values, use the constructor which accepts paramters
        /// </summary>
        protected TileBrush()
        {
        }
   
        #endregion Constructors
 
        /// <summary>
        /// Obtains the current bounds of the brush's content
        /// </summary>
        /// <param name="contentBounds"> Output bounds of content </param>            
        protected abstract void GetContentBounds(out Rect contentBounds);
 
        /// <summary>
        /// Obtains a matrix that maps the TileBrush's content to the coordinate
        /// space of the shape it is filling.
        /// </summary>
        /// <param name="shapeFillBounds">
        ///     Fill-bounds of the shape this brush is stroking/filling
        /// </param>
        /// <param name="tileBrushMapping">
        ///     Output matrix that maps the TileBrush's content to the coordinate
        ///     space of the shape it is filling
        /// </param>
        /// <SecurityNote>
        /// Critical as this code calls UnsafeNativeMethods.MilUtility_GetTileBrushMapping
        /// and MILUtilities.ConvertFromD3DMATRIX.
        /// Treat as safe because the first is simply a math utility function with no
        /// critical data exposure, and the second is passed pointers to type-correct data.
        /// </SecurityNote>            
        [SecurityCritical,SecurityTreatAsSafe]
        internal void GetTileBrushMapping(
            Rect shapeFillBounds,   
            out Matrix tileBrushMapping
            )
        {
            Rect contentBounds = Rect.Empty;            
            BrushMappingMode viewboxUnits = ViewboxUnits;
            bool brushIsEmpty = false;            
 
            // Initialize out-param 
            tileBrushMapping = Matrix.Identity;
 
            // Obtain content bounds for RelativeToBoundingBox ViewboxUnits
            //
            // If ViewboxUnits is RelativeToBoundingBox, then the tile-brush
            // transform is also dependent on the bounds of the content.
            if (viewboxUnits == BrushMappingMode.RelativeToBoundingBox)
            {
                GetContentBounds(out contentBounds);
 
                // If contentBounds is Rect.Empty then this brush renders nothing.
                // Set the empty flag & early-out.
                if (contentBounds == Rect.Empty)
                {
                    brushIsEmpty = true;
                }
            }
 
            //
            // Pass the properties to MilUtility_GetTileBrushMapping to calculate
            // the mapping, unless the brush is already determined to be empty
            //
            
            if (!brushIsEmpty)
            {
                //
                // Obtain properties that must be set into local variables
                // 
                
                Rect viewport = Viewport;
                Rect viewbox = Viewbox;
                Matrix transformValue;
                Matrix relativeTransformValue; 
 
                Transform.GetTransformValue(
                    Transform, 
                    out transformValue 
                    );
                
                Transform.GetTransformValue(
                    RelativeTransform,
                    out relativeTransformValue
                    );                
                
                unsafe
                {
                    D3DMATRIX d3dTransform;
                    D3DMATRIX d3dRelativeTransform;
 
                    D3DMATRIX d3dContentToShape;   
                    int brushIsEmptyBOOL;                
 
                    // Call MilUtility_GetTileBrushMapping, converting Matrix's to
                    // D3DMATRIX's when needed.
                    
                    MILUtilities.ConvertToD3DMATRIX(&transformValue, &d3dTransform);
                    MILUtilities.ConvertToD3DMATRIX(&relativeTransformValue, &d3dRelativeTransform);                
                    
                    MS.Win32.PresentationCore.UnsafeNativeMethods.MilCoreApi.MilUtility_GetTileBrushMapping(
                        &d3dTransform,
                        &d3dRelativeTransform,
                        Stretch,
                        AlignmentX,
                        AlignmentY,
                        ViewportUnits,
                        viewboxUnits,
                        &shapeFillBounds,
                        &contentBounds,
                        ref viewport,
                        ref viewbox,
                        out d3dContentToShape,
                        out brushIsEmptyBOOL
                        );
 
                    // Convert the brushIsEmpty flag from BOOL to a bool.                      
                    brushIsEmpty = (brushIsEmptyBOOL != 0);                     
 
                    // Set output matrix if the brush isn't empty.  Otherwise, the
                    // output of MilUtility_GetTileBrushMapping must be ignored.
                    if (!brushIsEmpty)
                    {
                        Matrix contentToShape;                        
                        MILUtilities.ConvertFromD3DMATRIX(&d3dContentToShape, &contentToShape);
 
                        // Set the out-param to the computed tile brush mapping
                        tileBrushMapping = contentToShape;                         
                    }   
                }
            }
        }    
    }
}