added History

Example sketch to demonstrate use of widget setValue() optional second argument

MicroView.cpp

@@ -1441,19 +1441,29 @@ void MicroViewWidget::setMaxValue(int16_t max) {
 */
 uint8_t MicroViewWidget::getMaxValLen() { return maxValLen; }
 
-/** \brief Set current value.
+/** \brief Set current value and update widget.
 
-	The current value of the widget is set to the variable passed in.
+	The current value of the widget is set to the variable passed in and the widget is drawn with the new value.
 */
 void MicroViewWidget::setValue(int16_t val) {
+	setValue(val, true);
+}
+
+/** \brief Set current value with optional update.
+
+	The current value of the widget is set to the variable passed in. The widget is drawn with the new value if the doDraw argument is true.
+*/
+void MicroViewWidget::setValue(int16_t val, boolean doDraw) {
 	if ((val<=maxValue) && (val>=minValue)) {
 		value = val;
 		valLen = getInt16PrintLen(val);
-		this->draw();
+		if (doDraw) {
+			this->draw();
+		}
 	}
 }
 
-/** \brief Get the print length of the value
+/** \brief Get the print length of the value.
 
 	Return the number of characters that would be printed using uView.print(value) for the current value.
 */

MicroView.h

@@ -241,6 +241,7 @@ public:
 	void setMinValue(int16_t min);
 	void setMaxValue(int16_t max);
 	void setValue(int16_t val);
+	void setValue(int16_t val, boolean doDraw);
 	uint8_t getValLen();
 	uint8_t getMaxValLen();
 	/** \brief Draw widget value overridden by child class. */
@@ -273,7 +274,7 @@ public:
 private:
 	void drawPointer();
 	uint8_t style, totalTicks;
-	bool noValDraw;
+	boolean noValDraw;
 	int16_t prevValue;
 };
 
@@ -286,7 +287,7 @@ public:
 private:
 	void drawPointer();
 	uint8_t style, radius;
-	bool noValDraw;
+	boolean noValDraw;
 	int16_t prevValue;
 };
 

README.md

@@ -92,6 +92,9 @@ void loop() {
 </code></pre>
 
 ## History
+**v1.23b: 29th March 2015 by Scott Allen**
+* added overloaded setValue() function to add a boolean argument doDraw which controls whether the display buffer is updated.
+
 **v1.22b: 4th October 2014 by Scott Allen and Ben Lewis**
 * replaced circleFill() with a faster algorithm, better looking circle - Ben Lewis
 * replaced sprintf with dedicated code, reduced program size - Scott Allen

examples/MicroViewWidgetBackground/MicroViewWidgetBackground.ino

@@ -0,0 +1,90 @@
+/*
+  MicroView Arduino Library
+  Copyright (C) 2015 GeekAmmo
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+  An example of using the optional second argument of the widget
+  setVal() function to update a widget without drawing the changes
+  to the screen buffer.
+
+  This, along with the widget reDraw() function, allows widgets to be
+  maintained in the "background" while other things are being displayed.
+
+  In this example,
+  a guage and a slider are both continually updated with the same
+  incrementing value. The widgets are alternately switched between the
+  "background" and being displayed, at random intervals.
+*/
+
+#include <MicroView.h>
+
+const int highVal = 100; // high value for widget range
+
+int wValue = 0; // value for widgets
+
+MicroViewWidget *guage1, *slider1;
+boolean guage1On, slider1On; // true if widget is being displayed
+
+void setup() {
+  uView.begin();
+
+  guage1 = new MicroViewGauge(32, 20, 0, highVal);
+  guage1On = false; // begin with guage1 off screen
+  uView.clear(PAGE);
+  
+  slider1 = new MicroViewSlider(8, 16, 0, highVal);
+  slider1On = true; // begin with slider1 on screen
+
+  // Init the random number generator using an
+  // unconnected analog pin.
+  randomSeed(analogRead(A0));
+}
+
+void loop() {
+  // Display a widget for a random number of value increments
+  for (int c = random(5, 16); c > 0; c--) {
+    uView.display();
+    delay(500);
+
+    wValue++;
+    if (wValue > highVal) {
+      wValue = 0;
+    }
+
+    // If the second setValue() argument is false, then
+    // the display buffer is not updated.
+    //
+    // In a practical application, the widgets would be set with
+    // the values that are being monitored.
+    guage1->setValue(wValue, guage1On);
+    slider1->setValue(wValue, slider1On);
+  }
+
+  // Switch which widget is being displayed
+  uView.clear(PAGE);
+
+  guage1On = !guage1On;
+  slider1On = !slider1On;
+
+  if (guage1On) {
+    guage1->reDraw();
+  }
+
+  if (slider1On) {
+    slider1->reDraw();
+  }
+}