/*This macro is based on the turtle graphics code by Norbert Vischer.
It creates Merz grid with semi-circular lines and points as non-destructive overlay.
Merz grid is a linear test system with built-in 2D isotropy,
so you do not need to rotate the grid to get isotropic line orientation.
Do not forget to "Set Scale" to get correct printout of the grid parameters,
which are reflected in the "Merz grid parameters" window.
"Central Points" makes two points in every tile.
"Line Points" makes 4 additional points per tile.
"Segmented lines" makes circular arcs with total length
2 times shorter than solid lines.
Grid constant a/l (area per line unit) is used to estimate total length
of a flat structure. Total length equals to number of intersections (between
linear feature and test lines) multiplied by PI/2 times the grid constant a/l.
Area per point can be used to estimate an area in 2D samples or volume density
in isotropic uniform random sections.
Test line per point (l/p) constant is used to estimate surface density (surface
area per unit volume) in isotropic uniform random sections.
Version: 1.0
Date: 04/09/2014
Author: Aleksandr Mironov amj-box@mail.ru
*/
requires("1.46b");
var
k57 = 180/PI,
turtleX = newArray(2000), turtleY = newArray(2000),
turtlePhi, tPtr, newX, newY, aa1, aa2, aa3, aa4, bb1, bb2, bb3, bb4;
macro "Merz_Grid" {
//help
html = ""
+"Merz Grid
"
+"is a linear test system with built-in 2D isotropy
"
+"Options:
"
+"Tile density - determines density of the grid
"
+"Central Points - two points per grid tile
"
+"Line Points - 4 additional points per grid tile
"
+"New Overlay - removes previous overlays
"
+"Random Offset - randomizes grid location
"
+"Random Phase - randomizes initial arc phase
"
+"Segmented lines - arcs with half of total length of solid lines
"
+"Set Scale to get correct printout of the grid parameters,
"
+"which are reflected in the 'Merz grid parameters' window
"
+"Useful parameters:
"
+"Area per point can be used to estimate an area in 2D samples
"
+"or volume density isotropic uniform random sections
"
+"Test line per point constant is used to estimate surface density
"
+"(surface area per unit volume) in isotropic uniform random sections
"
+"Grid constant a/l (area per line unit) is used to estimate total length
"
+"of a flat structure. Total length equals to number of intersections
"
+"multiplied by PI/2 times the grid constant a/l
"
//Creating dialog box
Dialog.create("Merz Grid, ver. 1.0");
Dialog.addNumber("Tile density =", 6,0,2,"within height");
Dialog.addCheckbox("Central Points", true);
Dialog.addCheckbox("Line Points (x2 of central)", true);
Dialog.addMessage("\n ");
Dialog.addCheckbox("New Overlay", true);
Dialog.addCheckbox("Random Offset", true);
Dialog.addCheckbox("Random Phase", true);
Dialog.addChoice("Line type", newArray("solid", "segmented"));
Dialog.addNumber("Line thickness =", 1,0,2,"pixels");
Dialog.addChoice("Color:", newArray("cyan", "red", "green", "magenta", "blue", "yellow", "orange", "black", "white"));
Dialog.addHelp(html);
Dialog.show();
//grid parameters
name = getTitle();
ntiles = Dialog.getNumber();
point = Dialog.getCheckbox();
points = Dialog.getCheckbox();
new = Dialog.getCheckbox();
if (new == true) Overlay.remove;
getDimensions(w, h, channels, slices, frames);
tile = h/ntiles;
//creating random offset
off1 = random;
off2 = random;
offset = Dialog.getCheckbox();
if (offset == false) off1 = off2 = 0;
xoff = -round(tile/2*off1);
yoff = -round(tile/2*off2);
//creating random phase
phase = random;
offphase = Dialog.getCheckbox();
if (offphase == false) phase = 0.1;
typeL = Dialog.getChoice();
t = Dialog.getNumber();
color = Dialog.getChoice();
setColor(color);
setLineWidth(t);
//tile parameters
step = tile*PI/40; //length of a step in pixels
nSteps = 10;//
dPhi = 9; //degrees between 2 steps
cycles = w/tile/2;
cycless = cycles+1;
xx1 = xoff;
yy1 = yoff;
//phase change
if (phase<0.25){
dPhi1=dPhi4=dPhi;
dPhi2=dPhi3=-dPhi;
phi=0;
}
else if (phase>=0.25 && phase<0.5){
dPhi1=dPhi4=-dPhi;
dPhi2=dPhi3=dPhi;
phi=0;
}
else if (phase>=0.5 && phase<0.75){
dPhi1=dPhi2=-dPhi;
dPhi3=dPhi4=dPhi;
phi=-90;
}
else { dPhi1=dPhi2=dPhi;
dPhi3=dPhi4=-dPhi;
phi=90;
}
//main loop
for (waves = 0; waves <= (ntiles+1); waves++){
turtleInit(xx1, yy1, phi);//starting point and angle
for (kk =0; kk=0.25 && phase<0.5) {
bb1=tile/32;
bb2=tile/32;
bb3=0;
bb4=tile/16;
}
else if (phase>=0.5 && phase<0.75) {
bb1=-tile/2;
bb2=-tile/2;
bb3=-tile/2-tile/32;
bb4=-tile/2+tile/32;
}
else {
bb1=tile/2;
bb2=tile/2;
bb3=tile/2-tile/32;
bb4=tile/2+tile/32;
}
}
//y for segment 3
function y_phaseDep3(){
if (phase<0.25){
bb1=tile/32;
bb2=tile/32;
bb3=0;
bb4=tile/16;
}
else if(phase>=0.25 && phase<0.5) {
bb1=-tile/32;
bb2=-tile/32;
bb3=-tile/16;
bb4=0;
}
else if (phase>=0.5 && phase<0.75){
bb1=tile/2;
bb2=tile/2;
bb3=tile/2-tile/32;
bb4=tile/2+tile/32;
}
else {
bb1=-tile/2;
bb2=-tile/2;
bb3=-tile/2-tile/32;
bb4=-tile/2+tile/32;
}
}
/*
Turtle routines
===============
at any moment, the turtle has position turtleX[tPtr], turtleY[tPtr],
and orientation turtlePhi.
Turtle array is 1-based.
Negative indices count from the back, so -1 addresses last vertex.
turtleX[0] and turtleY[0] are not used.
*/
//initialize
function turtleInit(xx, yy, phi){
tPtr =1;
turtleX[1]= xx;
turtleY[1]= yy;
turtlePhi= phi;
}
//create a selection
function turtleMakeSelection(type){
xx = newArray(tPtr);
yy = newArray(tPtr);
for (jj = 1; jj<=tPtr; jj++){
xx[jj-1] = turtleX[jj];
yy[jj-1] = turtleY[jj];
}
makeSelection(type, xx, yy);
}
//create line coordinates
function turtleLine(dPhi, rad){
turtlePhi -= dPhi;
while(turtlePhi < 0)
turtlePhi += 360;
while(turtlePhi >= 360)
turtlePhi -= 360;
dx = rad * cos(turtlePhi/k57);
dy = -rad * sin(turtlePhi/k57);
newX = turtleX[tPtr] + dx;
newY = turtleY[tPtr] + dy;
tPtr++;
turtleX[tPtr] = newX;
turtleY[tPtr] = newY;
}