public void Draw(GlyphBitmap other, int x, int y)
{
for (int j = 0; j < other.Height; j++)
{
for (int i = 0; i < other.Width; i++)
{
var srcOfs = i + j * other.Width;
var destOfs = (x + i) + (y + j) * this.Width;
Pixels[destOfs] = other.Pixels[srcOfs];
}
}
}
private void Rasterize(GlyphBitmap bitmap, float flatnessInPixels, List <Vertex> vertices, float scaleX, float scaleY, float shiftX, float shiftY, int XOff, int YOff, bool Invert)
{
float scale = scaleX < scaleY ? scaleX : scaleY;
int[] windingLengths;
List <Point> windings;
FlattenCurves(vertices, flatnessInPixels / scale, out windingLengths, out windings);
if (windings.Count > 0)
{
Rasterize(bitmap, windings, windingLengths, scaleX, scaleY, shiftX, shiftY, XOff, YOff, Invert);
}
}
/*
* Computes a distance field transform of a high resolution binary source channel and returns the result as a low resolution channel.
*
* scale_down : The amount the source channel will be scaled down.
* A value of 8 means the destination image will be 1/8th the size of the source
*
* spread: The spread in pixels before the distance field clamps to (zero/one).
* The valueis specified in units of the destination image. The spread in the source image will be spread*scale_down.
*/
public static GlyphBitmap CreateDistanceField(GlyphBitmap source, int scale, float spread)
{
var result = new GlyphBitmap(source.Width / scale, source.Height / scale);
var values = source.Pixels.Select(x => (x / 255.0f) - 0.5f).ToArray();
for (int y = 0; y < result.Height; y++)
{
for (int x = 0; x < result.Width; x++)
{
var sd = SignedDistance(values, source.Width, source.Height, x * scale, y * scale, spread);
var n = (sd + spread) / (spread * 2.0f);
var c = (byte)(n * 255);
var offset = x + y * result.Width;
result.Pixels[offset] = c;
}
}
return(result);
}
private GlyphBitmap GetGlyphBitmap(float scale_x, float scale_y, float shift_x, float shift_y, int glyph, out int xoff, out int yoff)
{
var vertices = GetGlyphShape(glyph);
if (scale_x == 0)
{
scale_x = scale_y;
}
if (scale_y == 0)
{
if (scale_x == 0)
{
throw new Exception("invalid scale");
}
scale_y = scale_x;
}
int ix0, iy0, ix1, iy1;
GetGlyphBitmapBox(glyph, scale_x, scale_y, shift_x, shift_y, out ix0, out iy0, out ix1, out iy1);
int w = (ix1 - ix0);
int h = (iy1 - iy0);
if (w <= 0 || h <= 0)
{
throw new Exception("invalid glyph size");
}
// now we get the size
var result = new GlyphBitmap(w, h);
xoff = ix0;
yoff = iy0;
Rasterize(result, 0.35f, vertices, scale_x, scale_y, shift_x, shift_y, ix0, iy0, true);
return(result);
}
private void RasterizeSortedEdges(GlyphBitmap bitmap, List <Edge> e, int vSubSamples, int offX, int off_y)
{
int eIndex = 0;
ActiveEdge active = null;
int max_weight = 255 / vSubSamples; // weight per vertical scanline
int y = off_y * vSubSamples;
int n = e.Count - 1;
var tempEdge = e[n];
tempEdge.y0 = (off_y + bitmap.Height) * vSubSamples + 1;
e[n] = tempEdge;
var scanline = new byte[bitmap.Width];
float scanY = 0;
int j = 0;
while (j < bitmap.Height)
{
for (int iii = 0; iii < bitmap.Width; iii++)
{
scanline[iii] = 0;
}
for (int s = 0; s < vSubSamples; s++)
{
// find center of pixel for this scanline
scanY = y + 0.5f;
// update all active edges;
// remove all active edges that terminate before the center of this scanline
var curr = active;
ActiveEdge prev = null;
while (curr != null)
{
if (curr.ey <= scanY)
{
// delete from list
if (prev != null)
{
prev.next = curr.next;
}
else
{
active = curr.next;
}
curr = curr.next;
}
else
{
curr.x += curr.dx; // advance to position for current scanline
prev = curr;
curr = curr.next; // advance through list
}
}
// resort the list if needed
bool changed;
do
{
changed = false;
curr = active;
prev = null;
while (curr != null && curr.next != null)
{
var prox = curr.next;
if (curr.x > prox.x)
{
if (prev == null)
{
active = prox;
}
else
{
prev.next = prox;
}
curr.next = prox.next;
prox.next = curr;
Console.WriteLine("Sorted " + curr.ey + " with " + prox.ey);
changed = true;
}
prev = curr;
curr = curr.next; // advance through list
}
} while (changed);
// insert all edges that start before the center of this scanline -- omit ones that also end on this scanline
while (e[eIndex].y0 <= scanY)
{
if (e[eIndex].y1 > scanY)
{
var z = CreateActiveEdge(e[eIndex], offX, scanY);
// find insertion point
if (active == null)
{
active = z;
}
else
if (z.x < active.x) // insert at front
{
z.next = active;
active = z;
}
else
{
// find thing to insert AFTER
var p = active;
while (p.next != null && p.next.x < z.x)
{
p = p.next;
}
// at this point, p->next->x is NOT < z->x
z.next = p.next;
p.next = z;
}
}
eIndex++;
}
// now process all active edges in XOR fashion
if (active != null)
{
FillActiveEdges(scanline, bitmap.Width, active, max_weight);
}
y++;
}
for (int iii = 0; iii < bitmap.Width; iii++)
{
if (scanline[iii] > 0) // OPTIMIZATION?
{
int ofs = iii + j * bitmap.Width;
bitmap.Pixels[ofs] = scanline[iii];
}
}
j++;
}
}
private void Rasterize(GlyphBitmap bitmap, List <Point> points, int[] windings, float scaleX, float scaleY, float shiftX, float shiftY, int XOff, int YOff, bool invert)
{
int ptOfs = 0;
float yScaleInv = invert ? -scaleY : scaleY;
// this value should divide 255 evenly; otherwise we won't reach full opacity
int vSubSamples = (bitmap.Height < 8) ? 15 : 5;
var edgeList = new List <Edge>(16);
int m = 0;
for (int i = 0; i < windings.Length; i++)
{
ptOfs = m;
m += windings[i];
int j = windings[i] - 1;
int k = 0;
while (k < windings[i])
{
int a = k;
int b = j;
var en = new Edge();
// skip the edge if horizontal
if (points[ptOfs + j].y != points[ptOfs + k].y)
{
// add edge from j to k to the list
en.invert = false;
if ((invert && points[ptOfs + j].y > points[ptOfs + k].y) || (!invert && points[ptOfs + j].y < points[ptOfs + k].y))
{
en.invert = true;
a = j;
b = k;
}
en.x0 = points[ptOfs + a].x * scaleX + shiftX;
en.y0 = points[ptOfs + a].y * yScaleInv * vSubSamples + shiftY;
en.x1 = points[ptOfs + b].x * scaleX + shiftX;
en.y1 = points[ptOfs + b].y * yScaleInv * vSubSamples + shiftY;
edgeList.Add(en);
}
j = k;
k++;
}
}
points.Clear();
// now sort the edges by their highest point (should snap to integer, and then by x)
edgeList.Sort((x, y) => EdgeCompare(x, y));
var temp = new Edge();
temp.y0 = 10000000;
edgeList.Add(temp);
// now, traverse the scanlines and find the intersections on each scanline, use xor winding rule
RasterizeSortedEdges(bitmap, edgeList, vSubSamples, XOff, YOff);
}
