Initial data commit

Task/Fractal-tree/D/fractal-tree-1.d

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+import std.stdio, std.math;
+
+enum width = 1000, height = 1000; // Image dimension.
+enum length = 400;                // Trunk size.
+enum scale = 6.0 / 10;            // Branch scale relative to trunk.
+
+void tree(in double x, in double y, in double length, in double angle) {
+    if (length < 1)
+        return;
+    immutable x2 = x + length * angle.cos;
+    immutable y2 = y + length * angle.sin;
+    writefln("<line x1='%f' y1='%f' x2='%f' y2='%f' " ~
+             "style='stroke:black;stroke-width:1'/>", x, y, x2, y2);
+    tree(x2, y2, length * scale, angle + PI / 5);
+    tree(x2, y2, length * scale, angle - PI / 5);
+}
+
+void main() {
+    "<svg width='100%' height='100%' version='1.1'
+     xmlns='http://www.w3.org/2000/svg'>".writeln;
+    tree(width / 2.0, height, length, 3 * PI / 2);
+    "</svg>".writeln;
+}

Task/Fractal-tree/D/fractal-tree-2.d

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+import grayscale_image, turtle;
+
+void tree(Color)(Image!Color img, ref Turtle t, in uint depth,
+                 in real step, in real scale, in real angle) {
+    if (depth == 0) return;
+    t.forward(img, step);
+    t.right(angle);
+    img.tree(t, depth - 1, step * scale, scale, angle);
+    t.left(2 * angle);
+    img.tree(t, depth - 1, step * scale, scale, angle);
+    t.right(angle);
+    t.forward(img, -step);
+}
+
+void main() {
+    auto img = new Image!Gray(330, 300);
+    auto t = Turtle(165, 270, -90);
+    img.tree(t, 10, 80, 0.7, 30);
+    img.savePGM("fractal_tree.pgm");
+}

Task/Fractal-tree/D/fractal-tree-3.d

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+import dfl.all;
+import std.math;
+
+class FractalTree: Form {
+
+    private immutable DEG_TO_RAD = PI / 180.0;
+
+    this() {
+        width = 600;
+        height = 500;
+        text = "Fractal Tree";
+        backColor = Color(0xFF, 0xFF, 0xFF);
+        startPosition = FormStartPosition.CENTER_SCREEN;
+        formBorderStyle = FormBorderStyle.FIXED_DIALOG;
+        maximizeBox = false;
+    }
+
+    private void drawTree(Graphics g, Pen p, int x1, int y1, double angle, int depth) {
+        if (depth == 0) return;
+        int x2 = x1 + cast(int) (cos(angle * DEG_TO_RAD) * depth * 10.0);
+        int y2 = y1 + cast(int) (sin(angle * DEG_TO_RAD) * depth * 10.0);
+        g.drawLine(p, x1, y1, x2, y2);
+        drawTree(g, p, x2, y2, angle - 20, depth - 1);
+        drawTree(g, p, x2, y2, angle + 20, depth - 1);
+    }
+
+    protected override void onPaint(PaintEventArgs ea){
+        super.onPaint(ea);
+        Pen p = new Pen(Color(0, 0xAA, 0));
+        drawTree(ea.graphics, p, 300, 450, -90, 9);
+    }
+}
+
+int main() {
+    int result = 0;
+    try {
+        Application.run(new FractalTree);
+    } catch(Exception e) {
+        msgBox(e.msg, "Fatal Error", MsgBoxButtons.OK, MsgBoxIcon.ERROR);
+        result = 1;
+    }
+    return result;
+}