package org.tw.pi.framebuffer;
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/*
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* This file is the JNI Java part of a Raspberry Pi FrameBuffer project.
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*
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* Created 2013 by Thomas Welsch (ttww@gmx.de).
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*
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* Do whatever you want to do with it :-)
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*
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**/
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import java.awt.Dimension;
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import java.awt.Graphics;
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import java.awt.image.BufferedImage;
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import java.awt.image.DataBufferInt;
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import javax.swing.JPanel;
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/**
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* This class is the Java front end for a simple to use FrameBuffer driver.
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* Simple draw in the BufferedImage and all changes are transfered to the FrameBuffer device.<p>
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* For testing purpose a dummy device is supported (via the devicename "dummy_160x128" instead of "/dev/fb1").<p<
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* The Java process needs write access to the frame buffer device file.
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* <p>
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* It's used to drive small bit mapped screens connected via SPI, see
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* http://www.sainsmart.com/blog/ada/
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* <p>
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* <p>
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* My Linux kernel config for SPI display was:
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* <pre>
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* CONFIG_FB_ST7735=y
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* CONFIG_FB_ST7735_PANEL_TYPE_RED_TAB=y
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* CONFIG_FB_ST7735_RGB_ORDER_REVERSED=y
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* CONFIG_FB_ST7735_MAP=y
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* CONFIG_FB_ST7735_MAP_RST_GPIO=25
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* CONFIG_FB_ST7735_MAP_DC_GPIO=24
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* CONFIG_FB_ST7735_MAP_SPI_BUS_NUM=0
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* CONFIG_FB_ST7735_MAP_SPI_BUS_CS=0
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* CONFIG_FB_ST7735_MAP_SPI_BUS_SPEED=16000000
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* CONFIG_FB_ST7735_MAP_SPI_BUS_MODE=0
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* </pre>
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* CONFIG_FB_ST7735_MAP_SPI_BUS_SPEED gives faster updates :-)
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* <p>
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* If you get the wrong colors, try the CONFIG_FB_ST7735_RGB_ORDER_REVERSED option !
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*/
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public class FrameBuffer {
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private static final int FPS = 60; // Max. update rate
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private String deviceName;
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private long deviceInfo; // Private data from JNI C
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private int width,height;
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private int bits;
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private BufferedImage img;
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private int[] imgBuffer;
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// -----------------------------------------------------------------------------------------------------------------
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private native long openDevice(String device);
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private native void closeDevice(long di);
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private native int getDeviceWidth(long di);
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private native int getDeviceHeight(long di);
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private native int getDeviceBitsPerPixel(long di);
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private native boolean updateDeviceBuffer(long di,int[] buffer);
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static {
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System.loadLibrary("FrameBufferJNI"); // FrameBufferJNI.dll (Windows) or FrameBufferJNI.so (Unixes)
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Open the named frame buffer device and starts the automatic update thread between the internal
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* BufferedImage and the device.
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*
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* @param deviceName e.g. /dev/fb1 or dummy_320x200
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*/
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public FrameBuffer(String deviceName) {
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this(deviceName,true);
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Open the named frame buffer device.
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*
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* @param deviceName e.g. /dev/fb1 or dummy_320x200
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* @param autoUpdate if true, starts the automatic update thread between the internal
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* BufferedImage and the device.
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*/
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public FrameBuffer(String deviceName, boolean autoUpdate) {
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this.deviceName = deviceName;
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deviceInfo = openDevice(deviceName);
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if (deviceInfo < 10) {
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throw new IllegalArgumentException("Init. for frame buffer "+deviceName+" failed with error code "+deviceInfo);
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}
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this.width = getDeviceWidth(deviceInfo);
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this.height = getDeviceHeight(deviceInfo);
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System.err.println("Open with "+deviceName+" ("+deviceInfo+")");
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System.err.println(" width "+getDeviceWidth(deviceInfo));
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System.err.println(" height "+getDeviceHeight(deviceInfo));
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System.err.println(" bpp "+getDeviceBitsPerPixel(deviceInfo));
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// We always use ARGB image type.
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img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
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imgBuffer = ((DataBufferInt) img.getRaster().getDataBuffer()).getBankData()[0];
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if (autoUpdate) new UpdateThread().start();
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}
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// -----------------------------------------------------------------------------------------------------------------
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private ScreenPanel screenPanel;
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/**
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* Returns a JPanel which represents the actual frame buffer device.
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*
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* @return JPanel...
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*/
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public JPanel getScreenPanel() {
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synchronized (deviceName) {
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if (screenPanel != null) throw new IllegalStateException("Only one screen panel supported");
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screenPanel = new ScreenPanel();
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return screenPanel;
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}
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Internal helper class for displaying the current frame buffer image via a JPanel.
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*/
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@SuppressWarnings("serial")
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private class ScreenPanel extends JPanel {
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public ScreenPanel() {
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setPreferredSize(new Dimension(FrameBuffer.this.width,FrameBuffer.this.height));
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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g.drawImage(img, 0, 0, null);
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}
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Internal helper class for refreshing the frame buffer display and/or JPanel.
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*/
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private class UpdateThread extends Thread {
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UpdateThread() {
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setDaemon(true);
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setName("FB "+deviceName+ " update");
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}
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@Override
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public void run() {
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final int SLEEP_TIME = 1000 / FPS;
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while (deviceInfo != 0) {
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if (updateScreen()) {
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if (screenPanel != null) {
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screenPanel.repaint();
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}
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}
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try {
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sleep(SLEEP_TIME);
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} catch (InterruptedException e) {
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break;
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}
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} // while
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}
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} // class UpdateThread
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Returns the BufferedImage for drawing. Anything your draw here is synchronizet to the frame buffer.
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*
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* @return BufferedImage of type ARGB.
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*/
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public BufferedImage getScreen() {
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return img;
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Close the device.
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*/
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public void close() {
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synchronized (deviceName) {
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closeDevice(deviceInfo);
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deviceInfo = 0;
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img = null;
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imgBuffer = null;
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}
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}
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// -----------------------------------------------------------------------------------------------------------------
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/**
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* Update the screen if no automatic sync is used (see constructor autoUpdate flag).
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* This method is normally called by the autoUpdate thread.
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*
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* @return true if the BufferedImage was changed since the last call.
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*/
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public boolean updateScreen() {
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synchronized (deviceName) {
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if (deviceInfo == 0) return false;
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return updateDeviceBuffer(deviceInfo,imgBuffer);
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}
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}
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} // of class
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