public CircleArc(Circle2D circle, double startAngle, double sweepAngle)
{
// For negative sweep angles we need to adjust the start angle so that we can make the sweep
// angle positive and be representing the same arc.
if (sweepAngle < 0.0)
{
startAngle += sweepAngle;
sweepAngle = -sweepAngle;
}
// Get the start angle in the range [0, 2*pi)
if (startAngle < 0.0)
{
startAngle = (startAngle % c_twoPi) + c_twoPi;
}
else
{
startAngle = startAngle % c_twoPi;
}
// Get the sweep angle in the range [0, 2*pi). Note that it's non-negative at this point.
sweepAngle %= c_twoPi;
m_circle = circle;
m_startAngle = startAngle;
m_sweepAngle = sweepAngle;
}
public static void Swap(ref Circle2D a, ref Circle2D b)
{
Circle2D temp = a;
a = b;
b = temp;
}
public unsafe void FillCircle(SimpleImage img, uint clr, Circle2D circle)
{
// Optimization: For composite-blending, we don't have do draw anything if the
// drawing color has an alpha value of zero
if (0 == (clr & 0xFF000000))
{
return;
}
// Soften radius (hard-coded for now)
float sr = 2.0f;
// Compute the inclusive y-starting point
int ystart = (int)Math.Floor(circle.MinY);
// Compute the inclusive y-ending point
int yend = (int)Math.Ceiling(circle.MaxY);
// Do a quick check to see if we're completely off the image
if (yend < 0 || ystart >= img.Height)
{
return;
}
// Constrain y-values, if needed
if (ystart < 0)
{
ystart = 0;
}
if (yend > img.Height - 1)
{
yend = img.Height - 1;
}
// Compute a float alpha value in the range [0.0, 1.0]
float alpha = (float)(clr >> 24) / 255.0f;
// Loop through rows of pixels
for (; ystart <= yend; ystart++)
{
// Compute intersections for this row
float minx, maxx;
circle.HLineIntersection((float)ystart, out minx, out maxx);
// Skip to the next row if there was no intersection
if (float.IsNaN(minx) || float.IsNaN(maxx))
{
continue;
}
// Compute the starting point on the left edge of the circle
int xLeft = (int)Math.Floor(minx);
// Skip this row if it's off the image
if (xLeft >= img.Width)
{
continue;
}
// Constrain if necessary
if (xLeft < 0)
{
xLeft = 0;
}
// Now compute the starting point on the right edge of the circle
int xRight = (int)Math.Ceiling(maxx);
// Skip if we're completely off the image
if (xRight < 0)
{
continue;
}
// Constrain, if necessary
if (xRight >= img.Width)
{
xRight = img.Width - 1;
}
// Make a pointer to this row of pixels
uint* row = &img.Pixels[ystart * img.Width + xLeft];
// Draw from the left edge until we hit a point where we're no longer within
// the softening radius distance from the edge
while (xLeft <= xRight)
{
float dist = circle.DistanceFromCenter((float)xLeft, (float)ystart);
if (dist >= circle.Radius)
{
// Advance to next pixel
row++;
xLeft++;
continue;
}
if (dist <= circle.Radius - sr)
{
break;
}
// Compute the alpha value
float newAFloat = (circle.Radius - dist) / sr * alpha * 255.0f;
// Blend
BlendComposite((clr & 0x00FFffFF) | (((uint)newAFloat) << 24), row);
// Advance to next pixel
row++;
xLeft++;
// See if we end up heading off the right edge of the image
if (xLeft >= img.Width)
{
break;
}
}
// If we drew pixels until we went off the image, then are done with this row
if (xLeft >= img.Width)
{
continue;
}
// It's possible, depending on the softening radius and which part of the circle we're
// rendering, that the entire row has already been processed. Remember that xLeft at
// this point is one to the right of the last pixel that was processed.
if (xRight < xLeft)
{
continue;
}
// Set the pointer to where we're starting
row = &img.Pixels[ystart * img.Width + xRight];
// Draw from the right edge until we hit a point where we're:
// a) no longer within the softening radius distance from the edge
// b) we're off the image (xRight < 0)
// or
// c) we're less than xLeft
while (xRight >= 0)
{
float dist = circle.DistanceFromCenter((float)xRight, (float)ystart);
if (dist >= circle.Radius)
{
// Advance to next pixel
row--;
xRight--;
continue;
}
if (dist <= circle.Radius - sr)
{
break;
}
// Compute the alpha value
float newAFloat = (circle.Radius - dist) / sr * alpha * 255.0f;
// Blend
BlendComposite((clr & 0x00FFffFF) | (((uint)newAFloat) << 24), row);
// Advance to next pixel
row--;
xRight--;
if (xRight < xLeft)
{
break;
}
}
// At this point we've processed from the left and right edges of the circle
// on this row and have taken care of all pixels that need edge softening. All
// that remains is filling pixels in between where we left off on the left and
// right.
if (xRight >= xLeft)
{
DrawHorizontalLine(xLeft, xRight, ystart, clr, img.Pixels, img.Width, img.Height,
BlendMode.AlphaComposite);
}
}
}
// TODO: Make this obey blending rules properly
public unsafe void DrawPieChart(uint* pxls, int width, int height,
PieChartSection[] sections, uint color)
{
if (0 == sections.Length)
{
throw new ArgumentException("Pie chart sections array cannot be empty");
}
// We need at least a 5x5 image
if (width < 5 || height < 5)
{
return;
}
// If the image is not square, we want non-zero starting points
int ystart = 0;
int yend = height - 1; // Inclusive upper bound
if (height > width)
{
ystart = (height - width) / 2;
yend = height - ystart;
}
float xcenter = (float)width / 2.0f;
float ycenter = (float)height / 2.0f;
double radius = Math.Min(xcenter, ycenter) - 2.0;
// Make a circle object for the pie chart area
Circle2D circle = new Circle2D(xcenter, ycenter, (float)radius);
// Compute the sum of all values in the pie sections
double sum = 0.0;
foreach (PieChartSection pcs in sections)
{
sum += pcs.Value;
}
// Make an angle table. This table stores the ending angle of each category. Also
// make a color table.
double[] angles = new double[sections.Length];
uint[] clrLookup = new uint[sections.Length];
int i = 0;
double angle = 0.0;
foreach (PieChartSection pcs in sections)
{
clrLookup[i] = pcs.Color;
angles[i] = pcs.Value / sum * (Math.PI * 2.0) + angle;
angle = pcs.Value / sum * (Math.PI * 2.0) + angle;
i++;
}
while (ystart <= yend)
{
// Compute the intersections of the scan line with the pie chart
float minx, maxx;
circle.HLineIntersection((float)ystart, out minx, out maxx);
// Clear the row if there isn't an intersection
if (float.IsNaN(minx) || float.IsNaN(maxx))
{
DrawHorizontalLine(0, width - 1, ystart, 0, pxls, width, height, BlendMode.None);
ystart++;
continue;
}
int xstart = (int)Math.Floor(minx);
int xend = (int)Math.Min(Math.Ceiling(maxx), (float)(width - 1));
uint* row = &pxls[ystart * width + xstart];
for (int x = xstart; x <= xend; x++)
{
// For each pixel, we want to start by computing the distance from the center
Vector2D pos = new Vector2D((float)x - xcenter, ycenter - (float)ystart);
double dist = pos.Length;
// Set the pixel to 0 if we're outside of the pie chart area
if (dist >= radius)
{
*row++ = 0;
continue;
}
// Compute the angle so we know what category of the pie we're in
angle = pos.GetCCWAngle();
i = 0;
while (angle > angles[i])
{
i++;
}
// Advance to the next pixel
*row++ = clrLookup[i];
}
ystart++;
}
// Draw lines between sections
if (sections.Length > 1)
{
List<Stadium> stadiums = new List<Stadium>();
foreach (double tempAngle in angles)
{
stadiums.Add(new Stadium(circle.Center,
new Vector2D(xcenter + (float)(radius * Math.Cos(tempAngle)),
ycenter - (float)(radius * Math.Sin(tempAngle))), 1.75f));
}
FillStadiums(new SimpleImage(width, height, pxls), color, stadiums.ToArray(), 2f);
}
// Draw a circular border around the pie chart
FrameCircle_Composite(circle, 3.5f, color, pxls, width, height);
}
/// <summary>
/// Draws an arc using alpha-compositing as the blend mode. Currently uses a hard-coded softening
/// distance value of 1.5 pixels.
/// </summary>
/// <param name="startAngle">Start angle, in radians</param>
/// <param name="sweepAngle">Sweep angle, in radians</param>
public unsafe void DrawArc(Circle2D circle, float lineThickness, double startAngle, double sweepAngle,
uint color, uint* pixels, int imageWidth, int imageHeight)
{
// Check parameters
if (lineThickness <= 0.0f)
{
throw new ArgumentException(
"Line thickness value must be a positive number");
}
// If the circle is degenerate then we have nothing to render
if (circle.IsDegenerate)
{
return;
}
// Special case: if the sweep angle is >= 2*pi then we just frame the whole circle
if (sweepAngle >= c_twoPi)
{
FrameCircle(circle, lineThickness, color, pixels, imageWidth, imageHeight);
return;
}
// Softening radius (hard-coded for now) (change method summary if this changes)
float sr = 1.5f;
// Compute lineThickness / 2 because it's used a lot
float lto2 = lineThickness / 2.0f;
double colorAlphaDouble = ((double)(color >> 24)) / 255.0;
// Another special case if the line is thick enough to extend in and past the center of the circle
if (circle.Radius - lto2 <= 0.0f)
{
FillCircle(new SimpleImage(imageWidth, imageHeight, pixels), color, circle);
return;
}
// Build the "outer" circle
Circle2D outer = new Circle2D(circle.Center, circle.Radius + lto2);
// Build the "inner" circle
Circle2D inner = new Circle2D(circle.Center, circle.Radius - lto2);
// Build the arc object
CircleArc ca = new CircleArc(circle, startAngle, sweepAngle);
// Find out the starting y-value
int ystart = (int)Math.Floor(ca.MinY - lto2);
// If it's below the bottom of the image then we have nothing to render
if (ystart >= imageHeight)
{
return;
}
// Make sure it's not < 0
if (ystart < 0)
{
ystart = 0;
}
// Now determine the inclusive ending y-value
int yend = (int)Math.Ceiling(ca.MaxY + lto2);
if (yend < 0) {return;}
if (yend >= imageHeight)
{
yend = imageHeight - 1;
}
// Loop through rows of pixels and render
while (ystart++ <= yend)
{
// Compute outer circle intersections
float ocx1, ocx2;
outer.HLineIntersection((float)ystart, out ocx1, out ocx2);
// If there's no intersection or the two x-values are equal, then move onto
// the next y-value
if (float.IsNaN(ocx1) || float.IsNaN(ocx2) || ocx1 == ocx2)
{
continue;
}
// Compute the inner circle intersections
float icx1, icx2;
inner.HLineIntersection((float)ystart, out icx1, out icx2);
float[] xvals;
if (float.IsNaN(icx1) || float.IsNaN(icx2) || icx1 == icx2)
{
// If there's no inner circle intersections then our array just has the two
// x-values for the outer intersection.
xvals = new float[] { ocx1, ocx2 };
}
else
{
xvals = new float[] { ocx1, icx1, icx2, ocx2 };
}
// Render between pairs of intersection points
for (int i = 0; i < xvals.Length; i+=2)
{
int x1 = (int)Math.Floor(xvals[i]);
if (x1 >= imageWidth)
{
continue;
}
if (x1 < 0) { x1 = 0; }
int x2 = (int)Math.Ceiling(xvals[i + 1]);
if (x2 >= imageWidth) { x2 = imageWidth - 1; }
uint* start = &pixels[ystart * imageWidth + x1];
uint* end = &pixels[ystart * imageWidth + x2];
while (start++ <= end)
{
float dist = ca.DistanceU(new Vector2D((float)x1, (float)ystart));
if (dist >= lto2)
{
x1++;
continue;
}
else if (dist > (lto2 - sr))
{
double alpha = (lto2 - dist) / sr;
alpha *= colorAlphaDouble;
uint clr = color & 0x00FFffFF;
clr |= (((uint)(alpha * 255.0)) << 24);
BlendComposite(clr, start);
}
else
{
BlendComposite(color, start);
}
x1++;
}
}
}
}
protected unsafe void FrameCircle_Composite(Circle2D circle, float frameThickness,
uint clr, uint* pxls, int w, int h)
{
// Softening radius (hard-coded for now)
float sr = 2.0f;
// Handle case where the frame is so thick that we just fill the whole circle
if (frameThickness / 2.0f >= circle.Radius + sr)
{
Circle2D newCircle = new Circle2D(circle.Center, circle.Radius + frameThickness / 2f);
FillCircle(new SimpleImage(w, h, pxls), clr, circle);
return;
}
// First make the outer and inner circle objects
Circle2D outer = new Circle2D(circle.Center, circle.Radius + frameThickness / 2.0f);
Circle2D inner = new Circle2D(circle.Center, circle.Radius - frameThickness / 2.0f);
int y = (int)Math.Max(0.0f, Math.Floor(outer.MinY));
for (; y < h; y++)
{
// Compute the x-intersection points for this y-value
float outMin, outMax, inMin, inMax;
outer.HLineIntersection((float)y, out outMin, out outMax);
inner.HLineIntersection((float)y, out inMin, out inMax);
// If there's not a valid intersection, then skip this row. Note that there
// could be an intersection with the outer circle and not the inner, but not
// the other way around.
if (float.IsNaN(outMin) || float.IsNaN(outMax))
{
continue;
}
float[] ranges;
if (float.IsNaN(inMin) || float.IsNaN(inMax))
{
// This means there's an intersection with the outer circle and not the
// inner. In this case we only have one continuous range of pixels to
// process for this row.
// Check to see if we're off the image
if (outMax < 0.0f || outMin > (float)(w - 1))
{
continue;
}
ranges = new float[] { outMin, outMax };
}
else
{
ranges = new float[] { outMin, inMin, inMax, outMax };
}
// Process the pixel ranges
for (int i = 0; i < ranges.Length; i += 2)
{
int x = (int)Math.Max(0.0f, Math.Floor(ranges[i]));
int maxx = (int)Math.Min((float)(w - 1), Math.Ceiling(ranges[i + 1]));
// Make a pointer to the pixel where we start rendering
uint* row = &pxls[y * w + x];
while (x <= maxx)
{
// Compute the distance from this pixel to the edge of the circle and
// soften if needed
float dist = circle.DistanceFromCenter(new Vector2D(x, y));
if (dist >= outer.Radius || dist <= inner.Radius)
{
x++;
row++;
continue;
}
if ((outer.Radius - dist) <= sr)
{
float newA = ((outer.Radius - dist) / sr) * 255.0f;
BlendComposite((clr & 0x00FFffFF) | (((uint)newA) << 24), row);
}
else if ((dist - inner.Radius) <= sr)
{
float newA = ((dist - inner.Radius) / sr) * 255.0f;
BlendComposite((clr & 0x00FFffFF) | (((uint)newA) << 24), row);
}
else
{
BlendComposite(clr, row);
}
x++;
row++;
}
}
}
}
public unsafe void FrameCircle(Circle2D circle, float frameThickness, uint clr,
uint* pxls, int imgWidth, int imgHeight)
{
FrameCircle_Composite(circle, frameThickness, clr, pxls, imgWidth, imgHeight);
}