public static SKImage RenderWithSkia(this CircularMaze maze,
RenderOptions renderOptions,
DistanceInfo distanceInfo,
ShortestPathInfo shortestPathInfo)
{
if (maze == null)
{
throw new ArgumentNullException(nameof(maze));
}
renderOptions = renderOptions ?? new RenderOptions();
var imageWidth = (GetRadiusAtRing(maze.RingCount) * 2) + (Margin * 2);
var imageCenter = imageWidth / 2;
var imageInfo = new SKImageInfo(imageWidth, imageWidth, SKColorType.Rgba8888, SKAlphaType.Premul);
using (var surface = SKSurface.Create(imageInfo))
{
surface.Canvas.Clear(SKColors.Black);
var whitePaint = new SKPaint {
Color = SKColors.White, StrokeWidth = CellLineWidth, Style = SKPaintStyle.Stroke
};
var renderedWalls = new HashSet <CellWall>();
foreach (var cell in maze.AllCells)
{
DrawRenderOptions(renderOptions, distanceInfo, cell, imageCenter, surface, shortestPathInfo, maze);
DrawWalls(maze, cell, renderedWalls, surface, imageCenter, whitePaint);
}
return(surface.Snapshot());
}
}
private static void DrawRenderOptions(RenderOptions renderOptions,
DistanceInfo distanceInfo,
Cell cell,
int imageCenter,
SKSurface surface,
ShortestPathInfo shortestPathInfo,
CircularMaze maze)
{
var position = maze.GetPositionOfCell(cell);
var centerOfCell = GetCenterOfCell(position, imageCenter);
var whitePaint = new SKPaint {
Color = SKColors.White, StrokeWidth = 1, 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
};
if (renderOptions.ShowGradientOfDistanceFromStart)
{
var path = new SKPath();
if (position.RingNumber > 0)
{
var innerRadius = GetRadiusAtRing(position.RingNumber - 1);
var outerRadius = GetRadiusAtRing(position.RingNumber);
var innerBounds = new SKRect(imageCenter - innerRadius,
imageCenter - innerRadius,
imageCenter + innerRadius,
imageCenter + innerRadius);
var outerBounds = new SKRect(imageCenter - outerRadius,
imageCenter - outerRadius,
imageCenter + outerRadius,
imageCenter + outerRadius);
var degreeDifference = position.EndingDegree - position.StartingDegree;
var firstLineCoords = GetCoords(outerRadius, position.EndingDegree);
var secondLineCoords = GetCoords(innerRadius, position.StartingDegree);
path.AddArc(innerBounds, NormalizeAngle(position.StartingDegree), NormalizeAngle(degreeDifference));
path.LineTo(imageCenter + firstLineCoords.x, imageCenter + firstLineCoords.y);
path.ArcTo(outerBounds, position.EndingDegree, -degreeDifference, false);
path.LineTo(imageCenter + secondLineCoords.x, imageCenter + secondLineCoords.y);
}
else
{
// Center cell should be fully shaded
path.AddCircle(imageCenter, imageCenter, CenterCellRadius);
}
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
};
surface.Canvas.DrawPath(path, paint);
}
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(), centerOfCell.x, centerOfCell.y, paint);
}
else if (renderOptions.ShowAllDistances && distanceInfo.DistanceFromStartMap.ContainsKey(cell))
{
var distance = distanceInfo.DistanceFromStartMap[cell];
surface.Canvas.DrawText(distance.ToString(), centerOfCell.x, centerOfCell.y, whitePaint);
}
else if (cell == maze.StartingCell)
{
surface.Canvas.DrawText("S", centerOfCell.x, centerOfCell.y, startPaint);
}
else if (cell == maze.FinishingCell)
{
surface.Canvas.DrawText("E", centerOfCell.x, centerOfCell.y, finishPaint);
}
}
private static void DrawWalls(CircularMaze maze,
Cell cell,
HashSet <CellWall> renderedWalls,
SKSurface surface,
int imageCenter,
SKPaint whitePaint)
{
var position = maze.GetPositionOfCell(cell);
foreach (var wall in cell.CellWalls)
{
if (renderedWalls.Contains(wall))
{
continue;
}
if (!wall.IsPassable)
{
var otherCellPosition = maze.GetPositionOfCell(wall.GetOtherCell(cell));
if (position.RingNumber == otherCellPosition.RingNumber)
{
// These cells border on the same ring, so find the angle that's the same and draw a line for it
var angle = Math.Abs(NormalizeAngle(position.StartingDegree) -
NormalizeAngle(otherCellPosition.EndingDegree)) < 0.001
? position.StartingDegree
: position.EndingDegree;
var lowerRing = Math.Min(position.RingNumber, otherCellPosition.RingNumber);
var innerRadius = GetRadiusAtRing(lowerRing - 1);
var outerRadius = GetRadiusAtRing(lowerRing);
var lineStart = GetCoords(innerRadius, angle);
var lineEnd = GetCoords(outerRadius, angle);
surface.Canvas.DrawLine(lineStart.x + imageCenter,
lineStart.y + imageCenter,
lineEnd.x + imageCenter,
lineEnd.y + imageCenter,
whitePaint);
}
else
{
var innerRing = Math.Min(position.RingNumber, otherCellPosition.RingNumber);
var radius = GetRadiusAtRing(innerRing);
var bounds = new SKRect(imageCenter - radius,
imageCenter - radius,
imageCenter + radius,
imageCenter + radius);
var startingDegree = Math.Max(position.StartingDegree, otherCellPosition.EndingDegree);
var endingDegree = Math.Min(position.EndingDegree, otherCellPosition.StartingDegree);
var path = new SKPath();
path.AddArc(bounds, startingDegree, endingDegree - startingDegree);
surface.Canvas.DrawPath(path, whitePaint);
}
}
renderedWalls.Add(wall);
}
if (position.RingNumber == maze.RingCount - 1 && cell != maze.FinishingCell && cell != maze.StartingCell)
{
// Last ring, so add rim of the maze
var radius = GetRadiusAtRing(maze.RingCount - 1);
var bounds = new SKRect(imageCenter - radius,
imageCenter - radius,
imageCenter + radius,
imageCenter + radius);
var startingDegree = position.StartingDegree;
var endingDegree = position.EndingDegree;
var path = new SKPath();
path.AddArc(bounds, startingDegree, endingDegree - startingDegree);
surface.Canvas.DrawPath(path, whitePaint);
}
}
