Graphics Reference
In-Depth Information
Listing 3.6: C# portion of the implementation of the Dürer algorithm.
public
Window1()
{
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InitializeComponent();
InitializeCommands();
// Now add some graphical items in the main Canvas,
whose name is "Paper"
gp =
this
.FindName(
"Paper"
)
as
GraphPaper;
// Build a table of vertices:
int
nPoints = 8;
int
nEdges = 12;
double
[,] vtable =
new double
[nPoints, 3]
{
{-0.5, -0.5, 2.5}, {-0.5, 0.5, 2.5},
{0.5, 0.5, 2.5}, ...};
// Build a table of edges
int
[,] etable =
new int
[nEdges, 2]
{
{0, 1}, {1, 2}, ...};
double
xmin = -0.5;
double
xmax = 0.5;
double
ymin = -0.5;
double
ymax = 0.5;
Point [] pictureVertices =
new
Point[nPoints];
double
scale = 100;
for
(
int
i = 0; i < nPoints; i++)
{
double
x = vtable[i, 0];
double
y = vtable[i, 1];
double
z = vtable[i, 2];
double
xprime = x / z;
double
yprime = y / z;
pictureVertices[i].X = scale
*
(1 - (xprime - xmin) /
(xmax - xmin));
pictureVertices[i].Y = scale
*
(yprime - ymin) /
(ymax - ymin);
gp.Children.Add(
new
Dot(pictureVertices[i].X,
pictureVertices[i].Y));
}
for
(
int
i = 0; i < nEdges; i++)
{
int
n1 = etable[i, 0];
int
n2 = etable[i, 1];
gp.Children.Add(
new
Segment(pictureVertices[n1],
pictureVertices[n2]));
}
...
}
We begin with a few comments. First, the code is not at all efficient (e.g.,
there was no need to declare the variables
x
,
y
, and
z
), but it follows the algo-
rithm very closely. For making graphics programs that are debuggable, this is an
excellent place to start in general: Don't be clever until your code works and you
