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Topic: translating image into points/rects (Read 1699 times) |
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_C
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translating image into points/rects
« on: Oct 18th, 2004, 1:18pm » |
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wrote a little code to get an imported image
with transparency build by some p5 forms.
useful eg if you want to map something onto
a mercator view of the earth ...
Code:
// filter for building images through grafic (p5) forms
// christian schaefer cser@gmx.de 10/2004
Pos positions;
Vector points;
BImage img;
int pixel[][];
int pixelLength[][];
int res=10; // resolution
float scale=1; // scale
float offsetX, offsetY; // sets image to middle of screen when mouse is there
void setup() {
size(800, 500); // when exporting the applet, its better to have ints for the size of it
background(99);
img = loadImage("welt_gray_gross.gif"); // this needs to be an image with transparent background
pixel = new int[img.width][img.height];
for(int i=0; i<img.height; i++) {
for(int j=0; j<img.width; j++) {
pixel[j][i] = img.pixels[i*img.width+j];
}
}
points = new Vector();
getPoints();
}
void loop() {
clear();
drawPoints();
}
void getPoints() {
for(int i=0; i<img.width; i+=res) {
for(int j=0; j<img.height; j+=res) {
if(alpha(pixel[i][j])>200) {
positions = new Pos();
positions.posx = i-img.width/2; // since the imagemode is to the upper left corner i do this here
positions.posy = j-img.height/2;
points.add(positions);
}
}
}
}
void drawPoints() {
offset();
translate(offsetX, offsetY, 0);
scale(scale);
for(Iterator i=points.iterator(); i.hasNext();) { // going throught the vector and draw the points stored in it
Pos temp = (Pos)i.next();
ellipse(temp.posx, temp.posy, res, res);
}
}
class Pos { // very simple class to store two points in
int posx;
int posy;
}
void keyPressed() {
switch(key) {
case RIGHT: scale+=0.2; break;
case LEFT : scale-=0.2; break;
}
}
void offset() {
offsetX+=((mouseX)*0.08-offsetX*0.08)*5;
offsetY+=((mouseY)*0.08-offsetY*0.08)*5;
}
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