Canvas doesn't work

[tomobmr]

Hello Community,

I'm on the verge of despair.

I've been trying for 2 days to get a Canvas example running so that I can later incorporate it into my code.

I want to try it with Canvas_Indexed later on, but at the moment, it seems to be failing at the very basics.

Please help!

What's happening:
The content of setup() is still being drawn. However, everything in loop() no longer appears on the display.
I've tried both flush() and draw16bitRGBBitmap().

#include <Arduino_GFX_Library.h>

/* Define the data bus and display settings */
Arduino_DataBus *bus = new Arduino_SWSPI(GFX_NOT_DEFINED /* DC */, 9 /* CS */, 10 /* SCK */, 11 /* MOSI */, 12 /* MISO */);

/* Initialize the display with appropriate parameters */
Arduino_GFX *output_display = new Arduino_ST7796(bus, 13 /* RST */, 1 /* rotation */, true /* IPS */, 272, 480, 0, 0, 24, 0);
Arduino_Canvas *canvas = new Arduino_Canvas(272 /* width */, 480 /* height */, output_display);

int value = 0;

void setup(void)
{
    output_display->begin();
    output_display->fillScreen(output_display->color565(50, 255, 255));
  
    canvas->begin();
}

void loop()
{
    // Fill canvas
    canvas->fillScreen(canvas->color565(0, 255, 0));
    canvas->fillRoundRect(value + 50, 50, 50, 50, 5, canvas->color565(255, 0, 0));  // Rounded rectangle with a red color - moving
    canvas->fillRoundRect(50, 150, 30, 30, 5, canvas->color565(0, 0, 255));         // Rounded rectangle with a blue color
    value = value + 10;

    // Use the new method to transfer the buffer content to the display
    //output_display->draw16bitRGBBitmap(0, 0, canvas->getFramebuffer(), 272, 480);    // Doesn't work too!!!
    canvas->flush();
    delay(1000);
}

Does anyone have a working code for Arduino_Canvas or Arduino_Canvas_Indexed?

[tomobmr]

For everyone who comes across this thread with the same question - here is the answer.

Including the option to display the memory used (for RP2040)

#include <malloc.h>

#include <Arduino_GFX_Library.h>

// Define color codes in RGB565 format
#define COLOR_WHITE      0xFFFF    // #FFFFFF
#define COLOR_GREY100    0xF7BE    // #F7F7F7
#define COLOR_GREY200    0xEF7D    // #ECEDED
#define COLOR_GREY300    0xDEFB    // #DEDEDE
#define COLOR_GREY400    0xC638    // #C5C5C7
#define COLOR_GREY500    0xAD75    // #ADADAD
#define COLOR_GREY600    0x9492    // #929294
#define COLOR_GREY700    0x5ACB    // #58585A
#define COLOR_GREY800    0x31C8    // #343A40
#define COLOR_BLACK      0x0000    // #000000
#define COLOR_REDDARK    0xA024    // #A70623
#define COLOR_RED        0xC0A4    // #C31727
#define COLOR_YELLOW     0xFDC2    // #FFBA10
#define COLOR_GREEN      0x13E7    // #107E3E

#define COLOR_Colors 14  // Total number of defined colors

// Define the data bus and display settings
Arduino_DataBus *bus = new Arduino_SWSPI(GFX_NOT_DEFINED /* DC */, 9 /* CS */, 10 /* SCK */, 11 /* MOSI */, 12 /* MISO */);
Arduino_GFX *gfx = new Arduino_ST7796(bus, 13 /* RST */, 1 /* rotation */, true /* IPS */, 272, 480, 0, 0, 24, 0);

// Create an Indexed Canvas with the display
Arduino_Canvas_Indexed *canvas = new Arduino_Canvas_Indexed(480, 272, gfx, 0, 0, 0, 0);

void getfreeRAM()
{
  struct mallinfo mi = mallinfo();

  int freeRAM = mi.fordblks;  // Free memory in bytes

  gfx->setCursor(300, 8);
  gfx->setTextColor(RED);
  gfx->printf("Free SRAM: %d", rp2040.getFreeHeap());    // free RAM in Bytes
  gfx->setCursor(150, 8);
  gfx->printf("Used SRAM: %d", rp2040.getUsedHeap());    // free RAM in Bytes
  gfx->setCursor(10, 8);
  gfx->printf("Total SRAM: %d", rp2040.getTotalHeap());    // free RAM in Bytes

}

void setup() {
  // Initialize the display
  gfx->begin();
  gfx->fillScreen(0x319F);  // Fill the screen

  getfreeRAM();
  delay(2000);

  canvas->begin(GFX_SKIP_OUTPUT_BEGIN);

  // Array containing all the defined colors
  uint16_t colors[COLOR_Colors] = {
      COLOR_WHITE,     // White
      COLOR_GREY100,   // Grey 100
      COLOR_GREY200,   // Grey 200
      COLOR_GREY300,   // Grey 300
      COLOR_GREY400,   // Grey 400
      COLOR_GREY500,   // Grey 500
      COLOR_GREY600,   // Grey 600
      COLOR_GREY700,   // Grey 700
      COLOR_GREY800,   // Grey 800
      COLOR_BLACK,     // Black
      COLOR_REDDARK,   // Dark Red
      COLOR_RED,       // Red
      COLOR_YELLOW,    // Yellow
      COLOR_GREEN,     // Green
  };

  // Assign colors to the canvas' color index
  for (int i = 0; i < COLOR_Colors; i++)
  {
    canvas->getColorIndex()[i] = colors[i];
  }

  canvas->setDirectUseColorIndex(true);  // Enable direct use of color indices

  canvas->fillScreen(5);

  // Calculate stripe parameters
  int margin = 20;
  int stripeTilt = 20; 
  int availableWidth = 480 - 2 * margin - stripeTilt;
  int stripeWidth = availableWidth / COLOR_Colors;

  // Draw diagonal stripes across the canvas
  for (int i = 0; i < COLOR_Colors; i++)
  {
    for (int j = 0; j < stripeWidth; j++)
    {
      canvas->drawLine(margin + stripeTilt + j + i * stripeWidth, margin, margin + j + i * stripeWidth, 272 - margin, i);
    }
  }

  // Update the display to show the canvas content
  canvas->flush();
  // Alternative way to draw the canvas
  // gfx->drawIndexedBitmap(0, 0, canvas->getFramebuffer(), canvas->getColorIndex(), 480, 272);
  getfreeRAM();


}

void loop() {

}