Minor performance improvements for ESP32

Remove legacy changes for double buffered SPI
Eliminate unecessary ESP32 SPI read/modify write
Eliminate two stage control bit changes (may impact some diplays with
setup/hold  timing and show ESP32 hardware register bug?)
Add single register write for CS and DC command
Make setAddrWindow smarter (as used in previous AVR library)
Improve compatibility with GFX sketches
Re-arrange comments slightly to improve positioning

Extensions/Smooth_font.cpp

@@ -78,6 +78,12 @@ void TFT_eSPI::loadFont(String fontName)
 
   _gFontFilename = "/" + fontName + ".vlw";
 
+  // Avoid a crash on the ESP32 if the file does not exist
+  if (SPIFFS.exists(_gFontFilename) == false) {
+    Serial.println("Font file " + fontName + " not found!");
+    return;
+  }
+
   fontFile = SPIFFS.open( _gFontFilename, "r");
 
   if(!fontFile) return;
@@ -479,7 +485,6 @@ void TFT_eSPI::drawGlyph(uint16_t code)
 void TFT_eSPI::showFont(uint32_t td)
 {
   if(!fontLoaded) return;
-//  fontFile = SPIFFS.open( _gFontFilename, "r" );
 
   if(!fontFile)
   {

TFT_Drivers/ST7735_Defines.h

@@ -9,15 +9,15 @@
 
 
 // Enumerate the different configurations
-#define INITR_GREENTAB  0x0
-#define INITR_REDTAB    0x1
-#define INITR_BLACKTAB  0x2
-#define INITR_GREENTAB2 0x3 // Use if you get random pixels on two edges of green tab display
-#define INITR_GREENTAB3 0x4 // Use if you get random pixels on edge(s) of 128x128 screen
-#define INITR_GREENTAB128 0x5 // Use if you only get part of 128x128 screen in rotation 0 & 1
+#define INITR_GREENTAB       0x0
+#define INITR_REDTAB         0x1
+#define INITR_BLACKTAB       0x2 // Display with no offsets
+#define INITR_GREENTAB2      0x3 // Use if you get random pixels on two edges of green tab display
+#define INITR_GREENTAB3      0x4 // Use if you get random pixels on edge(s) of 128x128 screen
+#define INITR_GREENTAB128    0x5 // Use if you only get part of 128x128 screen in rotation 0 & 1
 #define INITR_GREENTAB160x80 0x6 // Use if you only get part of 128x128 screen in rotation 0 & 1
-#define INITR_REDTAB160x80 0x7 // Added for https://www.aliexpress.com/item/ShengYang-1pcs-IPS-0-96-inch-7P-SPI-HD-65K-Full-Color-OLED-Module-ST7735-Drive/32918394604.html
-#define INITB           0xB
+#define INITR_REDTAB160x80   0x7 // Added for https://www.aliexpress.com/item/ShengYang-1pcs-IPS-0-96-inch-7P-SPI-HD-65K-Full-Color-OLED-Module-ST7735-Drive/32918394604.html
+#define INITB                0xB
 
 
 // Setup the tab color that will be used by the library setRotation() and setup command list