Initial Commit

Java/Processing/processing-3.3.6/modes/java/examples/Topics/GUI/Scrollbar/Scrollbar.pde

@@ -0,0 +1,121 @@
+/**
+ * Scrollbar. 
+ * 
+ * Move the scrollbars left and right to change the positions of the images. 
+ */
+
+HScrollbar hs1, hs2;  // Two scrollbars
+PImage img1, img2;  // Two images to load
+
+void setup() {
+  size(640, 360);
+  noStroke();
+  
+  hs1 = new HScrollbar(0, height/2-8, width, 16, 16);
+  hs2 = new HScrollbar(0, height/2+8, width, 16, 16);
+  
+  // Load images
+  img1 = loadImage("seedTop.jpg");
+  img2 = loadImage("seedBottom.jpg");
+}
+
+void draw() {
+  background(255);
+  
+  // Get the position of the img1 scrollbar
+  // and convert to a value to display the img1 image 
+  float img1Pos = hs1.getPos()-width/2;
+  fill(255);
+  image(img1, width/2-img1.width/2 + img1Pos*1.5, 0);
+  
+  // Get the position of the img2 scrollbar
+  // and convert to a value to display the img2 image
+  float img2Pos = hs2.getPos()-width/2;
+  fill(255);
+  image(img2, width/2-img2.width/2 + img2Pos*1.5, height/2);
+ 
+  hs1.update();
+  hs2.update();
+  hs1.display();
+  hs2.display();
+  
+  stroke(0);
+  line(0, height/2, width, height/2);
+}
+
+
+class HScrollbar {
+  int swidth, sheight;    // width and height of bar
+  float xpos, ypos;       // x and y position of bar
+  float spos, newspos;    // x position of slider
+  float sposMin, sposMax; // max and min values of slider
+  int loose;              // how loose/heavy
+  boolean over;           // is the mouse over the slider?
+  boolean locked;
+  float ratio;
+
+  HScrollbar (float xp, float yp, int sw, int sh, int l) {
+    swidth = sw;
+    sheight = sh;
+    int widthtoheight = sw - sh;
+    ratio = (float)sw / (float)widthtoheight;
+    xpos = xp;
+    ypos = yp-sheight/2;
+    spos = xpos + swidth/2 - sheight/2;
+    newspos = spos;
+    sposMin = xpos;
+    sposMax = xpos + swidth - sheight;
+    loose = l;
+  }
+
+  void update() {
+    if (overEvent()) {
+      over = true;
+    } else {
+      over = false;
+    }
+    if (mousePressed && over) {
+      locked = true;
+    }
+    if (!mousePressed) {
+      locked = false;
+    }
+    if (locked) {
+      newspos = constrain(mouseX-sheight/2, sposMin, sposMax);
+    }
+    if (abs(newspos - spos) > 1) {
+      spos = spos + (newspos-spos)/loose;
+    }
+  }
+
+  float constrain(float val, float minv, float maxv) {
+    return min(max(val, minv), maxv);
+  }
+
+  boolean overEvent() {
+    if (mouseX > xpos && mouseX < xpos+swidth &&
+       mouseY > ypos && mouseY < ypos+sheight) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  void display() {
+    noStroke();
+    fill(204);
+    rect(xpos, ypos, swidth, sheight);
+    if (over || locked) {
+      fill(0, 0, 0);
+    } else {
+      fill(102, 102, 102);
+    }
+    rect(spos, ypos, sheight, sheight);
+  }
+
+  float getPos() {
+    // Convert spos to be values between
+    // 0 and the total width of the scrollbar
+    return spos * ratio;
+  }
+}