static void Main(string[] args)
{
const string pngFileName = "rendering.png";
var maze = new TriangleMaze(20, 40, WallSetupAlgorithm.RecursiveBackTracker);
var mazeDistanceInfo = CellDistanceSolver.GetPassableDistancesFromCell(maze.StartingCell);
var mazeShortestPathInfo = ShortestPathSolver.Solve(maze.FinishingCell, mazeDistanceInfo);
var renderOptions = new RenderOptions
{
ShowGradientOfDistanceFromStart = true,
HighlightShortestPath = true,
//ShowAllDistances = true,
};
using (var image = maze.RenderWithSkia(renderOptions, mazeDistanceInfo, mazeShortestPathInfo))
using (var data = image.Encode(SKEncodedImageFormat.Png, 100))
using (var stream = File.OpenWrite(pngFileName))
{
data.SaveTo(stream);
}
}
public static SKImage RenderWithSkia(this TriangleMaze maze,
RenderOptions renderOptions,
DistanceInfo distanceInfo,
ShortestPathInfo shortestPathInfo)
{
if (maze == null)
{
throw new ArgumentNullException(nameof(maze));
}
renderOptions = renderOptions ?? new RenderOptions();
// All corner adjustments. Image starts 0,0 top left and goes downward, therefore top has to be adjusted
// by negative from center while bottom adjusted by positive from center.
var topMid = (x : 0, y : -HalfHeight);
var bottomRight = (x : HalfWidth, y : HalfHeight);
var bottomLeft = (x : -HalfWidth, y : HalfHeight);
var bottomMid = (x : 0, y : HalfHeight);
var topLeft = (x : -HalfWidth, y : -HalfHeight);
var topRight = (x : HalfWidth, y : -HalfHeight);
var imageWidth = (Margin * 2) + (maze.ColumnCount * HalfWidth) + HalfWidth;
var imageHeight = (Margin * 2) + (maze.RowCount * CellHeight);
var imageInfo = new SKImageInfo(imageWidth, imageHeight, SKColorType.Rgba8888, SKAlphaType.Premul);
using (var surface = SKSurface.Create(imageInfo))
{
surface.Canvas.Clear(SKColors.Black);
var whitePaint = new SKPaint {
Color = SKColors.White, StrokeWidth = CellLineWidth, TextAlign = SKTextAlign.Center
};
var startPaint = new SKPaint {
Color = SKColors.Green, StrokeWidth = 1, TextAlign = SKTextAlign.Center
};
var finishPaint = new SKPaint {
Color = SKColors.Red, StrokeWidth = 1, TextAlign = SKTextAlign.Center
};
var pathPaint = new SKPaint {
Color = SKColors.Yellow, StrokeWidth = 1, TextAlign = SKTextAlign.Center
};
foreach (var cell in maze.AllCells)
{
var(row, column) = maze.GetPositionOfCell(cell);
var centerX = Margin + (column * HalfWidth) + HalfWidth;
var centerY = Margin + (row * CellHeight) + HalfHeight;
var center = (x : centerX, y : centerY);
if (renderOptions.ShowGradientOfDistanceFromStart)
{
var finishingCellDistance = distanceInfo.DistanceFromStartMap[distanceInfo.FarthestCell];
var currentCellDistance = distanceInfo.DistanceFromStartMap[cell];
var intensity = (byte)(255 * (currentCellDistance / (decimal)finishingCellDistance));
var color = new SKColor(0, 0, intensity);
var paint = new SKPaint {
Color = color, Style = SKPaintStyle.Fill
};
var path = new SKPath();
if (TriangleMaze.IsCellPointingUp(row, column))
{
path.MoveTo(topMid.x + centerX, topMid.y + centerY);
path.LineTo(bottomRight.x + centerX, bottomRight.y + centerY);
path.LineTo(bottomLeft.x + centerX, bottomLeft.y + centerY);
path.LineTo(topMid.x + centerX, topMid.y + centerY);
}
else
{
path.MoveTo(bottomMid.x + centerX, bottomMid.y + centerY);
path.LineTo(topLeft.x + centerX, topLeft.y + centerY);
path.LineTo(topRight.x + centerX, topRight.y + centerY);
path.LineTo(bottomMid.x + centerX, bottomMid.y + centerY);
}
surface.Canvas.DrawPath(path, paint);
}
var passableWalls = new[] { false, false, false }; // left, right, vertical
foreach (var cellWall in cell.CellWalls.Where(x => x.IsPassable))
{
var otherCellPosition = maze.GetPositionOfCell(cellWall.GetOtherCell(cell));
if (otherCellPosition.row == row && otherCellPosition.column < column)
{
passableWalls[0] = true;
}
else if (otherCellPosition.row == row && otherCellPosition.column > column)
{
passableWalls[1] = true;
}
else
{
passableWalls[2] = true;
}
}
if (TriangleMaze.IsCellPointingUp(row, column))
{
if (!passableWalls[0])
{
surface.Canvas.DrawLine(GetCenteredPoint(bottomLeft, center), GetCenteredPoint(topMid, center), whitePaint);
}
if (!passableWalls[1])
{
surface.Canvas.DrawLine(GetCenteredPoint(topMid, center), GetCenteredPoint(bottomRight, center), whitePaint);
}
if (!passableWalls[2])
{
surface.Canvas.DrawLine(GetCenteredPoint(bottomRight, center), GetCenteredPoint(bottomLeft, center), whitePaint);
}
}
else
{
if (!passableWalls[0])
{
surface.Canvas.DrawLine(GetCenteredPoint(bottomMid, center), GetCenteredPoint(topLeft, center), whitePaint);
}
if (!passableWalls[1])
{
surface.Canvas.DrawLine(GetCenteredPoint(topRight, center), GetCenteredPoint(bottomMid, center), whitePaint);
}
if (!passableWalls[2])
{
surface.Canvas.DrawLine(GetCenteredPoint(topLeft, center), GetCenteredPoint(topRight, center), whitePaint);
}
}
var textYAdjust = TriangleMaze.IsCellPointingUp(row, column)
? HalfHeight / 3
: -HalfHeight / 3;
if (renderOptions.HighlightShortestPath && shortestPathInfo.IsCellInPath(cell))
{
var paint = cell == maze.StartingCell ? startPaint
: cell == maze.FinishingCell ? finishPaint
: pathPaint;
var distance = distanceInfo.DistanceFromStartMap[cell];
surface.Canvas.DrawText(distance.ToString(), center.x, center.y + textYAdjust, paint);
}
else if (renderOptions.ShowAllDistances && distanceInfo.DistanceFromStartMap.ContainsKey(cell))
{
var distance = distanceInfo.DistanceFromStartMap[cell];
surface.Canvas.DrawText(distance.ToString(), center.x, center.y + textYAdjust, whitePaint);
}
else if (cell == maze.StartingCell)
{
surface.Canvas.DrawText("S", center.x, center.y + textYAdjust, startPaint);
}
else if (cell == maze.FinishingCell)
{
surface.Canvas.DrawText("E", center.x, center.y + textYAdjust, finishPaint);
}
}
return(surface.Snapshot());
}
}
