Paints on a WriteableBitmap with a stylized airbrush - CSharp System.Windows.Media.Imaging

CSharp examples for System.Windows.Media.Imaging:WriteableBitmap

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Description

Paints on a WriteableBitmap with a stylized airbrush

Demo Code

// (c) Copyright Microsoft Corporation.
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.IO;//from   w ww  .  j a va 2s . c o  m
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Text;
using System.Linq;
using System.Collections.Generic;
using System;

public class Main{
        /// <summary>
        /// Paints on a pbgra32 WriteableBitmap with a stylized airbrush
        /// </summary>
        /// <param name="bmp">The bitmap to modify</param>
        /// <param name="from">The starting point of the stroke</param>
        /// <param name="to">The end point of the stroke</param>
        /// <param name="color">The color of the stroke</param>
        /// <param name="size">The size of the stroke</param>
        public static unsafe void Airbrush(WriteableBitmap bmp, Point from, Point to, Color color, int size)
        {
            Random r = new Random();

            if (bmp == null) return;

            bmp.Lock();
            
            // Create a line segment representation
            LineSegment segment = new LineSegment(from, to);

            // Get a bounding box for the painted area
            BoundingBox bitmapbounds = new BoundingBox();
            BoundingBox segmentbounds = new BoundingBox();

            bitmapbounds.AddPoint(0, 0, 0);
            bitmapbounds.AddPoint(bmp.PixelWidth - 1, bmp.PixelHeight - 1, 0);

            segmentbounds.AddPoint((int)from.X, (int)from.Y, size + AirbrushDotRadius);
            segmentbounds.AddPoint((int)to.X, (int)to.Y, size + AirbrushDotRadius);
            segmentbounds.Clip(bitmapbounds);

            UInt32* start = (UInt32*)bmp.BackBuffer.ToPointer();
            int stride = bmp.BackBufferStride / sizeof(UInt32);
            // Move from 'from' to 'to' along timestep intervals, with one dot painted per interval
            for (int i = 0; i < AirbrushDots; i++)
            {
                int x, y;
                segment.Interpolate(i, AirbrushDots, out x, out y);

                int dist = r.Next() % size;
                double angle = r.NextDouble() * 2 * Math.PI;

                double dx = Math.Cos(angle) * dist;
                double dy = Math.Sqrt(dist * dist - dx * dx);
                if(angle > Math.PI) dy = -dy;

                int bx = x + (int)dx;
                int by = y + (int)dy;

                BoundingBox dotbounds = new BoundingBox();

                dotbounds.AddPoint(bx,by,AirbrushDotRadius);
                dotbounds.Clip(bitmapbounds);

                for (int k = dotbounds.Top, row = 0; k < dotbounds.Bottom; k++, y++, row++)
                    for (int j = dotbounds.Left, col = 0; j < dotbounds.Right; j++, col++)
                        WriteAlphaBlended(start + stride * k + j, Color.FromArgb(AirbrushDotKernel[row][col], color.R, color.G, color.B));
            }

            bmp.AddDirtyRect(new Int32Rect(segmentbounds.Left, segmentbounds.Top, segmentbounds.Width, segmentbounds.Height));
            bmp.Unlock();
        }
}

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