public void Set(Scanline scan, bool newValue)
{
int x = scan.X;
while (x < scan.X + scan.Length)
{
Set(x, scan.Y, newValue);
++x;
}
}
public void Invert(Scanline scan)
{
int x = scan.X;
while (x < scan.X + scan.Length)
{
Invert(x, scan.Y);
++x;
}
}
public override bool Equals(object?obj)
{
if (obj is Scanline)
{
Scanline rhs = (Scanline)obj;
return(x == rhs.x && y == rhs.y && length == rhs.length);
}
else
{
return(false);
}
}
public static Scanline[] GetScans(this Point[] points)
{
int ymax = 0;
// Build edge table
Edge[] edgeTable = new Edge[points.Length];
int edgeCount = 0;
for (int i = 0; i < points.Length; ++i) {
Point top = points[i];
Point bottom = points[(i + 1) % points.Length];
int dy;
if (top.Y > bottom.Y) {
Point temp = top;
top = bottom;
bottom = temp;
}
dy = bottom.Y - top.Y;
if (dy != 0) {
edgeTable[edgeCount] = new Edge (top.Y, bottom.Y, top.X << 8, (((bottom.X - top.X) << 8) / dy));
ymax = Math.Max (ymax, bottom.Y);
++edgeCount;
}
}
// Sort edge table by miny
for (int i = 0; i < edgeCount - 1; ++i) {
int min = i;
for (int j = i + 1; j < edgeCount; ++j)
if (edgeTable[j].miny < edgeTable[min].miny)
min = j;
if (min != i) {
Edge temp = edgeTable[min];
edgeTable[min] = edgeTable[i];
edgeTable[i] = temp;
}
}
// Compute how many scanlines we will be emitting
int scanCount = 0;
int activeLow = 0;
int activeHigh = 0;
int yscan1 = edgeTable[0].miny;
// we assume that edgeTable[0].miny == yscan
while (activeHigh < edgeCount - 1 &&
edgeTable[activeHigh + 1].miny == yscan1) {
++activeHigh;
}
while (yscan1 <= ymax) {
// Find new edges where yscan == miny
while (activeHigh < edgeCount - 1 &&
edgeTable[activeHigh + 1].miny == yscan1) {
++activeHigh;
}
int count = 0;
for (int i = activeLow; i <= activeHigh; ++i) {
if (edgeTable[i].maxy > yscan1) {
++count;
}
}
scanCount += count / 2;
++yscan1;
// Remove edges where yscan == maxy
while (activeLow < edgeCount - 1 &&
edgeTable[activeLow].maxy <= yscan1) {
++activeLow;
}
if (activeLow > activeHigh)
activeHigh = activeLow;
}
// Allocate scanlines that we'll return
Scanline[] scans = new Scanline[scanCount];
// Active Edge Table (AET): it is indices into the Edge Table (ET)
int[] active = new int[edgeCount];
int activeCount = 0;
int yscan2 = edgeTable[0].miny;
int scansIndex = 0;
// Repeat until both the ET and AET are empty
while (yscan2 <= ymax) {
// Move any edges from the ET to the AET where yscan == miny
for (int i = 0; i < edgeCount; ++i) {
if (edgeTable[i].miny == yscan2) {
active[activeCount] = i;
++activeCount;
}
}
// Sort the AET on x
for (int i = 0; i < activeCount - 1; ++i) {
int min = i;
for (int j = i + 1; j < activeCount; ++j)
if (edgeTable[active[j]].x < edgeTable[active[min]].x)
min = j;
if (min != i) {
int temp = active[min];
active[min] = active[i];
active[i] = temp;
}
}
// For each pair of entries in the AET, fill in pixels between their info
for (int i = 0; i < activeCount; i += 2) {
Edge el = edgeTable[active[i]];
Edge er = edgeTable[active[i + 1]];
int startx = (el.x + 0xff) >> 8; // ceil(x)
int endx = er.x >> 8; // floor(x)
scans[scansIndex] = new Scanline (startx, yscan2, endx - startx);
++scansIndex;
}
++yscan2;
// Remove from the AET any edge where yscan == maxy
int k = 0;
while (k < activeCount && activeCount > 0) {
if (edgeTable[active[k]].maxy == yscan2) {
// remove by shifting everything down one
for (int j = k + 1; j < activeCount; ++j)
active[j - 1] = active[j];
--activeCount;
} else {
++k;
}
}
// Update x for each entry in AET
for (int i = 0; i < activeCount; ++i)
edgeTable[active[i]].x += edgeTable[active[i]].dxdy;
}
return scans;
}
public static Scanline[] GetScans(this Point[] points)
{
int ymax = 0;
// Build edge table
Edge[] edgeTable = new Edge[points.Length];
int edgeCount = 0;
for (int i = 0; i < points.Length; ++i)
{
Point top = points[i];
Point bottom = points[(i + 1) % points.Length];
int dy;
if (top.Y > bottom.Y)
{
Point temp = top;
top = bottom;
bottom = temp;
}
dy = bottom.Y - top.Y;
if (dy != 0)
{
edgeTable[edgeCount] = new Edge(top.Y, bottom.Y, top.X << 8, (((bottom.X - top.X) << 8) / dy));
ymax = Math.Max(ymax, bottom.Y);
++edgeCount;
}
}
// Sort edge table by miny
for (int i = 0; i < edgeCount - 1; ++i)
{
int min = i;
for (int j = i + 1; j < edgeCount; ++j)
{
if (edgeTable[j].miny < edgeTable[min].miny)
{
min = j;
}
}
if (min != i)
{
Edge temp = edgeTable[min];
edgeTable[min] = edgeTable[i];
edgeTable[i] = temp;
}
}
// Compute how many scanlines we will be emitting
int scanCount = 0;
int activeLow = 0;
int activeHigh = 0;
int yscan1 = edgeTable[0].miny;
// we assume that edgeTable[0].miny == yscan
while (activeHigh < edgeCount - 1 &&
edgeTable[activeHigh + 1].miny == yscan1)
{
++activeHigh;
}
while (yscan1 <= ymax)
{
// Find new edges where yscan == miny
while (activeHigh < edgeCount - 1 &&
edgeTable[activeHigh + 1].miny == yscan1)
{
++activeHigh;
}
int count = 0;
for (int i = activeLow; i <= activeHigh; ++i)
{
if (edgeTable[i].maxy > yscan1)
{
++count;
}
}
scanCount += count / 2;
++yscan1;
// Remove edges where yscan == maxy
while (activeLow < edgeCount - 1 &&
edgeTable[activeLow].maxy <= yscan1)
{
++activeLow;
}
if (activeLow > activeHigh)
{
activeHigh = activeLow;
}
}
// Allocate scanlines that we'll return
Scanline[] scans = new Scanline[scanCount];
// Active Edge Table (AET): it is indices into the Edge Table (ET)
int[] active = new int[edgeCount];
int activeCount = 0;
int yscan2 = edgeTable[0].miny;
int scansIndex = 0;
// Repeat until both the ET and AET are empty
while (yscan2 <= ymax)
{
// Move any edges from the ET to the AET where yscan == miny
for (int i = 0; i < edgeCount; ++i)
{
if (edgeTable[i].miny == yscan2)
{
active[activeCount] = i;
++activeCount;
}
}
// Sort the AET on x
for (int i = 0; i < activeCount - 1; ++i)
{
int min = i;
for (int j = i + 1; j < activeCount; ++j)
{
if (edgeTable[active[j]].x < edgeTable[active[min]].x)
{
min = j;
}
}
if (min != i)
{
int temp = active[min];
active[min] = active[i];
active[i] = temp;
}
}
// For each pair of entries in the AET, fill in pixels between their info
for (int i = 0; i < activeCount; i += 2)
{
Edge el = edgeTable[active[i]];
Edge er = edgeTable[active[i + 1]];
int startx = (el.x + 0xff) >> 8; // ceil(x)
int endx = er.x >> 8; // floor(x)
scans[scansIndex] = new Scanline(startx, yscan2, endx - startx);
++scansIndex;
}
++yscan2;
// Remove from the AET any edge where yscan == maxy
int k = 0;
while (k < activeCount && activeCount > 0)
{
if (edgeTable[active[k]].maxy == yscan2)
{
// remove by shifting everything down one
for (int j = k + 1; j < activeCount; ++j)
{
active[j - 1] = active[j];
}
--activeCount;
}
else
{
++k;
}
}
// Update x for each entry in AET
for (int i = 0; i < activeCount; ++i)
{
edgeTable[active[i]].x += edgeTable[active[i]].dxdy;
}
}
return(scans);
}
public void Set(Scanline scan, bool newValue)
{
int x = scan.X;
while (x < scan.X + scan.Length)
{
Set(x, scan.Y, newValue);
++x;
}
}
public void Invert(Scanline scan)
{
int x = scan.X;
while (x < scan.X + scan.Length)
{
Invert(x, scan.Y);
++x;
}
}
