Screentweak (#214)

* adding pid

* hiding functions

* precision of value

docs/examples/line-follower-pid.md

@@ -1,3 +1,4 @@
+# Gradien follower PID + calibration
 
 ```blocks
 let lasterror = 0
@@ -5,12 +6,45 @@ let D = 0
 let I = 0
 let P = 0
 let error = 0
+let setpoint = 0
+let max = 0
+let min = 0
+let v = 0
+v = sensors.color3.light(LightIntensityMode.Reflected)
+min = v
+max = v
+setpoint = v
+while (!(brick.buttonEnter.wasPressed())) {
+    brick.clearScreen()
+    brick.showString("Move robot on terrain", 1)
+    brick.showString("Press ENTER when done", 2)
+    v = sensors.color3.light(LightIntensityMode.Reflected)
+    min = Math.min(min, v)
+    max = Math.max(max, v)
+    setpoint = (max + min) / 2
+    brick.showValue("v", v, 3)
+    brick.showValue("min", min, 4)
+    brick.showValue("max", v, 5)
+    brick.showValue("setpoint", setpoint, 6)
+    loops.pause(100)
+}
 loops.forever(function () {
-    error = sensors.color3.light(LightIntensityMode.Reflected) - 35
+    brick.clearScreen()
+    v = sensors.color3.light(LightIntensityMode.Reflected)
+    brick.showValue("light", v, 1)
+    error = v - setpoint
+    brick.showValue("error", error, 2)
     P = error * 5
+    brick.showValue("P", P, 3)
     I = I + error * 0.01
+    brick.showValue("I", I, 4)
     D = (error - lasterror) * 0.2
+    brick.showValue("D", D, 5)
     motors.largeBC.steer(P + (I + D), 100)
     lasterror = error
+    if (brick.buttonEnter.wasPressed()) {
+        motors.largeBC.setSpeed(0)
+        brick.buttonDown.pauseUntil(ButtonEvent.Click)
+    }
 })
 ```

libs/core/screen.ts

@@ -58,7 +58,7 @@ namespace brick {
         }
     }
 
-    export function setPixel(on: boolean, x: number, y: number) {
+    function setPixel(on: boolean, x: number, y: number) {
         x |= 0
         y |= 0
         if (0 <= x && x < DAL.LCD_WIDTH && 0 <= y && y < DAL.LCD_HEIGHT)
@@ -101,6 +101,7 @@ namespace brick {
     //% weight=96 group="Screen" inlineInputMode="inline" blockGap=8
     //% line.min=1 line.max=10
     export function showValue(name: string, value: number, line: number) {
+        value = Math.round(value * 1000) / 1000;
         showString((name ? name + ": " : "") + value, line);        
     }
 
@@ -140,12 +141,9 @@ namespace brick {
      */
     //% blockId=screen_show_image block="show image %image=screen_image_picker"
     //% weight=100 group="Screen" blockGap=8
-    export function showImage(image: Image, delay: number = 400) {
+    export function showImage(image: Image) {
         if (!image) return;
         image.draw(0, 0, Draw.Normal);
-        delay = Math.max(0, delay);
-        if (delay > 0)
-            loops.pause(delay);
     }
 
     /**
@@ -170,7 +168,7 @@ namespace brick {
         screen.clear();
     }
 
-    export function drawRect(x: number, y: number, w: number, h: number, mode = Draw.Normal) {
+    function drawRect(x: number, y: number, w: number, h: number, mode = Draw.Normal) {
         x |= 0;
         y |= 0;
         w |= 0;