Arc test (Bodmer#2316)

* Add smooth arc drawing function

Update ESP8266 architecture reference
Add pushMaskedImage() to render 16bpp images with a 1bpp mask (used for transparent PNG images plus with sprites)

New functions added using drawArc:
drawSmoothArc
drawSmoothCircle
drawSmoothRoundRect
New sqrt_fraction() added to improve smooth graphics performance on processors without a FPU (e.g. RP2040)

Faster alphaBlend() function added which retains 6bpp for green

Rename swap_coord() to transpose()

* Update TFT_eSPI.cpp

* Add arc examples

Author: Bodmer

Extensions/Sprite.cpp

@@ -1257,8 +1257,8 @@ void  TFT_eSprite::pushImage(int32_t x, int32_t y, int32_t w, int32_t h, const u
 // Intentionally not constrained to viewport area, does not manage 1bpp rotations
 void TFT_eSprite::setWindow(int32_t x0, int32_t y0, int32_t x1, int32_t y1)
 {
-  if (x0 > x1) swap_coord(x0, x1);
-  if (y0 > y1) swap_coord(y0, y1);
+  if (x0 > x1) transpose(x0, x1);
+  if (y0 > y1) transpose(y0, y1);
 
   int32_t w = width();
   int32_t h = height();
@@ -1700,13 +1700,13 @@ void TFT_eSprite::drawLine(int32_t x0, int32_t y0, int32_t x1, int32_t y1, uint3
 
   bool steep = abs(y1 - y0) > abs(x1 - x0);
   if (steep) {
-    swap_coord(x0, y0);
-    swap_coord(x1, y1);
+    transpose(x0, y0);
+    transpose(x1, y1);
   }
 
   if (x0 > x1) {
-    swap_coord(x0, x1);
-    swap_coord(y0, y1);
+    transpose(x0, x1);
+    transpose(y0, y1);
   }
 
   int32_t dx = x1 - x0, dy = abs(y1 - y0);;

Processors/TFT_eSPI_ESP8266.h

@@ -19,7 +19,7 @@
 #define DMA_BUSY_CHECK // DMA not available, leave blank
 
 // Initialise processor specific SPI functions, used by init()
-#if (!defined (SUPPORT_TRANSACTIONS) && defined (ESP8266))
+#if (!defined (SUPPORT_TRANSACTIONS) && defined (ARDUINO_ARCH_ESP8266))
   #define INIT_TFT_DATA_BUS \
     spi.setBitOrder(MSBFIRST); \
     spi.setDataMode(TFT_SPI_MODE); \

Processors/TFT_eSPI_RP2040.c

@@ -577,7 +577,7 @@ void TFT_eSPI::pushPixels(const void* data_in, uint32_t len){
 
 
 ////////////////////////////////////////////////////////////////////////////////////////
-#ifdef RP2040_DMA // DMA functions for 16 bit SPI and 8 bit parallel displays
+#ifdef RP2040_DMA // DMA functions for 16 bit SPI and 8/16 bit parallel displays
 ////////////////////////////////////////////////////////////////////////////////////////
 /*
 These are created in header file:

Processors/TFT_eSPI_RP2040.h

@@ -65,9 +65,20 @@
   #define DMA_BUSY_CHECK
 #endif
 
+// Handle high performance MHS RPi display type
+#if  defined (MHS_DISPLAY_TYPE)  && !defined (RPI_DISPLAY_TYPE)
+  #define RPI_DISPLAY_TYPE
+#endif
+
 #if !defined (RP2040_PIO_INTERFACE) // SPI
-  // Initialise processor specific SPI functions, used by init()
-  #define INIT_TFT_DATA_BUS  // Not used
+
+  #if  defined (MHS_DISPLAY_TYPE) // High speed RPi TFT type always needs 16 bit transfers
+    // This swaps to 16 bit mode, used for commands so wait avoids clash with DC timing
+    #define INIT_TFT_DATA_BUS hw_write_masked(&spi_get_hw(SPI_X)->cr0, (16 - 1) << SPI_SSPCR0_DSS_LSB, SPI_SSPCR0_DSS_BITS)
+  #else
+    // Initialise processor specific SPI functions, used by init()
+    #define INIT_TFT_DATA_BUS  // Not used
+  #endif
 
   // Wait for tx to end, flush rx FIFO, clear rx overrun
   #define SPI_BUSY_CHECK while (spi_get_hw(SPI_X)->sr & SPI_SSPSR_BSY_BITS) {};     \
@@ -141,7 +152,7 @@
   #if !defined (RP2040_PIO_INTERFACE)// SPI
     //#define DC_C sio_hw->gpio_clr = (1ul << TFT_DC)
     //#define DC_D sio_hw->gpio_set = (1ul << TFT_DC)
-    #if  defined (RPI_DISPLAY_TYPE)
+    #if  defined (RPI_DISPLAY_TYPE) && !defined (MHS_DISPLAY_TYPE)
       #define DC_C digitalWrite(TFT_DC, LOW);
       #define DC_D digitalWrite(TFT_DC, HIGH);
     #else
@@ -167,7 +178,7 @@
   #define CS_H // No macro allocated so it generates no code
 #else
   #if !defined (RP2040_PIO_INTERFACE) // SPI
-    #if  defined (RPI_DISPLAY_TYPE)
+    #if  defined (RPI_DISPLAY_TYPE) && !defined (MHS_DISPLAY_TYPE)
       #define CS_L digitalWrite(TFT_CS, LOW);
       #define CS_H digitalWrite(TFT_CS, HIGH);
     #else
@@ -287,7 +298,28 @@
   // Macros to write commands/pixel colour data to other displays
   ////////////////////////////////////////////////////////////////////////////////////////
   #else
-    #if  defined (RPI_DISPLAY_TYPE) // RPi TFT type always needs 16 bit transfers
+    #if  defined (MHS_DISPLAY_TYPE) // High speed RPi TFT type always needs 16 bit transfers
+      // This swaps to 16 bit mode, used for commands so wait avoids clash with DC timing
+      #define tft_Write_8(C)      while (spi_get_hw(SPI_X)->sr & SPI_SSPSR_BSY_BITS) {}; \
+                                  hw_write_masked(&spi_get_hw(SPI_X)->cr0, (16 - 1) << SPI_SSPCR0_DSS_LSB, SPI_SSPCR0_DSS_BITS); \
+                                  spi_get_hw(SPI_X)->dr = (uint32_t)((C) | ((C)<<8)); \
+                                  while (spi_get_hw(SPI_X)->sr & SPI_SSPSR_BSY_BITS) {}; \
+
+      // Note: the following macros do not wait for the end of transmission
+
+      #define tft_Write_16(C)     while (!spi_is_writable(SPI_X)){}; spi_get_hw(SPI_X)->dr = (uint32_t)(C)
+
+      #define tft_Write_16N(C)    while (!spi_is_writable(SPI_X)){}; spi_get_hw(SPI_X)->dr = (uint32_t)(C)
+
+      #define tft_Write_16S(C)    while (!spi_is_writable(SPI_X)){}; spi_get_hw(SPI_X)->dr = (uint32_t)(C)<<8 | (C)>>8
+
+      #define tft_Write_32(C)     spi_get_hw(SPI_X)->dr = (uint32_t)((C)>>16); spi_get_hw(SPI_X)->dr = (uint32_t)(C)
+
+      #define tft_Write_32C(C,D)  spi_get_hw(SPI_X)->dr = (uint32_t)(C); spi_get_hw(SPI_X)->dr = (uint32_t)(D)
+
+      #define tft_Write_32D(C)    spi_get_hw(SPI_X)->dr = (uint32_t)(C); spi_get_hw(SPI_X)->dr = (uint32_t)(C)
+
+    #elif  defined (RPI_DISPLAY_TYPE) // RPi TFT type always needs 16 bit transfers
       #define tft_Write_8(C)   spi.transfer(C); spi.transfer(C)
       #define tft_Write_16(C)  spi.transfer((uint8_t)((C)>>8));spi.transfer((uint8_t)((C)>>0))
       #define tft_Write_16N(C) spi.transfer((uint8_t)((C)>>8));spi.transfer((uint8_t)((C)>>0))