1/8 Scan Panel Example

#154 #204

Also supports chaining.

3 files changed, 229 insertions, 0 deletions

diff --git a/examples/One_Eight_1_8_ScanPanel/1_8_ScanPanel.h b/examples/One_Eight_1_8_ScanPanel/1_8_ScanPanel.h
new file mode 100644
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+++ b/examples/One_Eight_1_8_ScanPanel/1_8_ScanPanel.h
@@ -0,0 +1,69 @@
+#ifndef _ESP32_ONE_EIGHT_SCAN_PANEL
+#define _ESP32_ONE_EIGHT_SCAN_PANEL
+
+#include <ESP32-VirtualMatrixPanel-I2S-DMA.h>
+
+/* This class inherits all the goodness of the VirtualMatrixPanel class used to created
+   large displays of chained panels, but does trickery to convert from 1/16 to 1/8
+   DMA output.
+
+   Some guidance given by looking at hzeller's code, in relation to the 'stretch factor'
+   concept where these panels are really double width and half the height, from the perspective
+   of the digital input required to get the 'real world' resolution and output.
+   https://github.com/hzeller/rpi-rgb-led-matrix/blob/master/lib/multiplex-mappers.cc
+*/
+class OneEightScanPanel : public VirtualMatrixPanel
+{
+  public:
+    using VirtualMatrixPanel::VirtualMatrixPanel; // inherit VirtualMatrixPanel's constructor(s)
+
+  protected:
+    /* Convert Real World 'VirtualMatrixPanel' co-ordinates (i.e. Real World pixel you're looking at
+       on the panel or chain of panels, per the chaining configuration) to a 1/8 panels
+       double 'stretched' and 'squished' coordinates which is what needs to be sent from the
+       DMA buffer.
+
+       Note: Look at the One_Eight_1_8_ScanPanel code and you'll see that the DMA buffer is setup
+       as if the panel is 2 * W and 0.5 * H !
+    */
+    VirtualCoords getCoords(int16_t &x, int16_t &y);
+
+}; // end class header note the ;
+
+
+
+inline VirtualCoords OneEightScanPanel::getCoords(int16_t &x, int16_t &y) {
+  VirtualMatrixPanel::getCoords(x, y); // call to base to update coords for chaining approach
+  
+  if ( coords.x == -1 || coords.y == -1 ) { // Co-ordinates go from 0 to X-1 remember! width() and height() are out of range!
+    return coords;
+  }
+
+/*
+  Serial.print("VirtualMatrixPanel Mapping ("); Serial.print(x, DEC); Serial.print(","); Serial.print(y, DEC); Serial.print(") ");
+  // to
+  Serial.print("to ("); Serial.print(coords.x, DEC);  Serial.print(",");  Serial.print(coords.y, DEC);   Serial.println(") ");  
+ */
+  if ( (y & 8) == 0) { 
+    coords.x += ((coords.x / panelResX)+1)*panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+  }
+  else {
+    coords.x += (coords.x / panelResX)*panelResX; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+  }
+
+  // http://cpp.sh/4ak5u
+  // Real number of DMA y rows is half reality
+  // coords.y = (y / 16)*8 + (y & 0b00000111);   
+  coords.y = (y >> 4)*8 + (y & 0b00000111);   
+
+ /*
+  Serial.print("OneEightScanPanel Mapping ("); Serial.print(x, DEC); Serial.print(","); Serial.print(y, DEC); Serial.print(") ");
+  // to
+  Serial.print("to ("); Serial.print(coords.x, DEC);  Serial.print(",");  Serial.print(coords.y, DEC);   Serial.println(") ");
+ */
+ 
+  return coords;
+}
+
+
+#endif
diff --git a/examples/One_Eight_1_8_ScanPanel/One_Eight_1_8_ScanPanel.ino b/examples/One_Eight_1_8_ScanPanel/One_Eight_1_8_ScanPanel.ino
new file mode 100644
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+++ b/examples/One_Eight_1_8_ScanPanel/One_Eight_1_8_ScanPanel.ino
@@ -0,0 +1,147 @@
+/*************************************************************************
+ * Description: 
+ * 
+ * The underlying implementation of the ESP32-HUB75-MatrixPanel-I2S-DMA only
+ * supports output to 1/16 or 1/32 scan panels - which means outputting 
+ * two lines at the same time, 16 or 32 rows apart. This cannot be changed
+ * at the DMA layer as it would require a messy and complex rebuild of the 
+ * library's DMA internals.
+ *
+ * However, it is possible to connect 1/8 scan panels to this same library and
+ * 'trick' the output to work correctly on these panels by way of adjusting the
+ * pixel co-ordinates that are 'sent' to the ESP32-HUB75-MatrixPanel-I2S-DMA
+ * library.
+ * 
+ **************************************************************************/
+#include "ESP32-HUB75-MatrixPanel-I2S-DMA.h"
+
+// Virtual Display to re-map co-ordinates such that they draw correctly on a 32x16 1/4 Scan panel
+#include "1_8_ScanPanel.h" 
+
+
+  // Panel configuration
+  #define PANEL_RES_X 64 // Number of pixels wide of each INDIVIDUAL panel module. 
+  #define PANEL_RES_Y 32 // Number of pixels tall of each INDIVIDUAL panel module.
+  
+  
+  #define NUM_ROWS 1 // Number of rows of chained INDIVIDUAL PANELS
+  #define NUM_COLS 2 // Number of INDIVIDUAL PANELS per ROW
+  
+  // ^^^ NOTE: DEFAULT EXAMPLE SETUP IS FOR A CHAIN OF TWO x 1/8 SCAN PANELS
+    
+  // Change this to your needs, for details on VirtualPanel pls read the PDF!
+  #define SERPENT true
+  #define TOPDOWN false
+  
+  // placeholder for the matrix object
+  MatrixPanel_I2S_DMA *dma_display = nullptr;
+
+  // placeholder for the virtual display object
+  OneEightScanPanel  *OneEightMatrixDisplay = nullptr;
+  
+  /******************************************************************************
+   * Setup!
+   ******************************************************************************/
+  void setup()
+  {
+    delay(250);
+   
+    Serial.begin(115200);
+    Serial.println(""); Serial.println(""); Serial.println("");
+    Serial.println("*****************************************************");
+    Serial.println("*         1/8 Scan Panel Demonstration              *");
+    Serial.println("*****************************************************");
+  
+/* 
+     // 62x32 1/8 Scan Panels don't have a D and E pin!
+	 
+	 HUB75_I2S_CFG::i2s_pins _pins = {
+      R1_PIN, G1_PIN, B1_PIN, R2_PIN, G2_PIN, B2_PIN, 
+      A_PIN, B_PIN, C_PIN, D_PIN, E_PIN, 
+      LAT_PIN, OE_PIN, CLK_PIN
+	 };
+*/
+  	HUB75_I2S_CFG mxconfig(
+  				PANEL_RES_X*2,   	        // DO NOT CHANGE THIS
+  				PANEL_RES_Y/2,   	        // DO NOT CHANGE THIS
+  				NUM_ROWS*NUM_COLS     		// DO NOT CHANGE THIS
+  				//,_pins			// Uncomment to enable custom pins
+  	);
+    
+    mxconfig.clkphase = false; // Change this if you see pixels showing up shifted wrongly by one column the left or right.
+    
+  	//mxconfig.driver   = HUB75_I2S_CFG::FM6126A;     // in case that we use panels based on FM6126A chip, we can set it here before creating MatrixPanel_I2S_DMA object
+  
+  	// OK, now we can create our matrix object
+  	dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+  
+  	// let's adjust default brightness to about 75%
+  	dma_display->setBrightness8(96);    // range is 0-255, 0 - 0%, 255 - 100%
+  
+  	// Allocate memory and start DMA display
+  	if( not dma_display->begin() )
+  	  Serial.println("****** !KABOOM! I2S memory allocation failed ***********");
+
+   
+    dma_display->clearScreen();
+    delay(500);
+    
+  	// create OneEightMatrixDisplaylay object based on our newly created dma_display object
+  	OneEightMatrixDisplay = new OneEightScanPanel((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, SERPENT, TOPDOWN);
+
+  }
+
+  
+  void loop() {
+
+      // What the panel sees from the DMA engine!
+      for (int i=PANEL_RES_X*2+10; i< PANEL_RES_X*(NUM_ROWS*NUM_COLS)*2; i++)
+      {
+        dma_display->drawLine(i, 0, i, 7, dma_display->color565(255, 0, 0)); // red
+        delay(10);
+      }
+          
+      dma_display->clearScreen();
+      delay(1000);
+/*
+      // Try again using the pixel / dma memory remapper
+      for (int i=PANEL_RES_X+5; i< (PANEL_RES_X*2)-1; i++)
+      {
+        OneEightMatrixDisplay->drawLine(i, 0, i, 7, dma_display->color565(0, 0, 255)); // blue    
+        delay(10);
+      } 
+*/
+
+      // Try again using the pixel / dma memory remapper
+      int offset = PANEL_RES_X*((NUM_ROWS*NUM_COLS)-1);
+      for (int i=0; i< PANEL_RES_X; i++)
+      {
+        OneEightMatrixDisplay->drawLine(i+offset, 0, i+offset, 7, dma_display->color565(0, 0, 255)); // blue
+        OneEightMatrixDisplay->drawLine(i+offset, 8, i+offset, 15, dma_display->color565(0, 128,0)); // g        
+        OneEightMatrixDisplay->drawLine(i+offset, 16, i+offset, 23, dma_display->color565(128, 0,0)); // red
+        OneEightMatrixDisplay->drawLine(i+offset, 24, i+offset, 31, dma_display->color565(0, 128, 128)); // blue        
+        delay(10);
+      } 
+
+      delay(1000);
+
+
+      // Print on each chained panel 1/8 module!
+      // This only really works for a single horizontal chain
+      for (int i = 0; i < NUM_ROWS*NUM_COLS; i++)
+      {
+        OneEightMatrixDisplay->setTextColor(OneEightMatrixDisplay->color565(255, 255, 255));
+        OneEightMatrixDisplay->setCursor(i*PANEL_RES_X+7, OneEightMatrixDisplay->height()/3); 
+      
+        // Red text inside red rect (2 pix in from edge)
+        OneEightMatrixDisplay->print("Panel " + String(i+1));
+        OneEightMatrixDisplay->drawRect(1,1, OneEightMatrixDisplay->width()-2, OneEightMatrixDisplay->height()-2, OneEightMatrixDisplay->color565(255,0,0));
+      
+        // White line from top left to bottom right
+        OneEightMatrixDisplay->drawLine(0,0, OneEightMatrixDisplay->width()-1, OneEightMatrixDisplay->height()-1, OneEightMatrixDisplay->color565(255,255,255));
+      }
+
+      delay(2000);
+      dma_display->clearScreen();
+  
+  } // end loop
diff --git a/examples/One_Eight_1_8_ScanPanel/README.md b/examples/One_Eight_1_8_ScanPanel/README.md
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+++ b/examples/One_Eight_1_8_ScanPanel/README.md
@@ -0,0 +1,13 @@
+# Using this library with 32x16 1/8 Scan Panels
+
+## Problem
+ESP32-HUB75-MatrixPanel-I2S-DMA library will not display output correctly with 1/8 scan panels such [as this](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/154) by default.
+
+## Solution
+It is possible to connect 1/8 scan panels to this library and 'trick' the output to work correctly on these panels by way of adjusting the pixel co-ordinates that are 'sent' to the ESP32-HUB75-MatrixPanel-I2S-DMA library (in this example, it is the 'dmaOutput' class).
+
+Creation of a 'OneEighthScanMatrixPanel.h' class which sends an adjusted drawPixel() x,y co-ordinates to the underlying ESP32-HUB75-MatrixPanel-I2S-DMA library's drawPixel routine, to trick the output to look pixel perfect. 
+
+Refer to the '1_8_ScanPanel.h' logic which builds upon the library's core 'Virtual Display' (ESP32-VirtualMatrixPanel-I2S-DMA.h) to also support chaining of 1/8 Scan Panels. Refer to 'ChainedPanels' example on how to configure panel chaining to create bigger displays.
+
+