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u8gvsu8g2.md

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+[tocstart]: # (toc start)
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+  * [U8g vs. U8g2](#u8g-vs-u8g2)
+    * [Improvements](#improvements)
+    * [How to port U8g code?](#how-to-port-u8g-code)
+
+[tocend]: # (toc end)
+
+# U8g vs. U8g2
+
+## Improvements
+
+ * Full "RAM" memory buffer without picture loop
+ * Arduino SPI and TWI Libraries instead of custom code
+ * Support for Unicode and UTF-8
+ * Faster compilation
+ * High speed text only API (U8x8)
+ * Hardware 180 degree rotation for some displays available
+ * Tested with AVR, SAM and ESP8266 boards
+
+## How to port U8g code?
+
+### Major Changes (Code rework required)
+
+ * The name of the include file has changed: Use `#include "U8g2lib.h"`
+ * The native type for pixel coordinates has changed to `u8g2_uint_t`.
+Use the following line to redefine this at the beginning of your code
+    `typedef u8g2_uint_t u8g_uint_t;`
+ * Old Arduino IDE 00xx (before 1.00) is not supported any more.
+ARDUINO macro must be >= 100
+ * `begin()` must be called (this was optional in U8glib)
+ * Constructor contains name of communicaton interface and 
+also contains the display orientation as first argument.
+ * u8g2.drawStr90 does not exist any more, use
+      `u8g2_SetFontDirection()`
+ * "P" versions of the string functions are not yet implemented.
+This includes drawStrP(), getStrWidthP(), etc
+Use the print function with the F() macro instead. See also the
+PrintHelloWorld and PrintProgmem examples.
+ * In U8glib font transparency was defined in the `begin()` statement. This is now
+handled by `setFontMode()`. 
+ * `U8G_PROGMEM` is now called `U8X8_PROGMEM`.
+ * Screen rotation is handled by the constructor in U8g2.
+The functions undoRotation, setRot90, setRot180 and setRot270 are
+replaced by the first argument of the U8g2 constructor.
+ * Screen scaling is not there in u8g2.
+This is completly removed, there are no corresponding function in u8g2 
+for undoScale() and setScale2x2().
+ * `setColorEntry()`, `setHiColor()`, `setHiColorByRGB()`, `setRGB`: Not supported any more
+(u8g2 focus are monochrome displays, use Ucglib instead)
+ * `getMode()`: Is not available any more because there is only one monochrome mode.	
+ * `setDefaultForegroundColor()`, `setDefaultBackgroundColor()` and 
+`setDefaultMidColor()` are not required any more. These functions do not
+exist in U8g2. Use `setDrawColor()` instead.
+ * `getFontLineSpacing()` and `setFontLineSpacingFactor()` are not supported any more. Instead you can get the line spacing by calculating the difference `getAscent()-getDescent()`.
+ * `getStrPixelWidth()` is replaced by `getStrWidth()` 
+ * `setHardwareBackup()` not supported any more (and hopefully not required any more). 
+ * Cursor functions are not available. This includes:
+`setCursorFont()`, `setCursorStyle()`, `setCursorPos()`, `setCursorColor()`,
+`enableCursor()`, `disableCursor()`, `drawCursor()`
+ * Virtual screen handling is not supported:
+`setVirtualScreenDimension()`, `addToVirtualScreen()`
+	
+### Minor Changes (Code update might be required)
+
+* U8g2 `drawTriangle()` expects signed arguments (u8glib expects unsigned arguments)
+* U8g2 has different font names. Some of the old font names are known to u8g2 and are
+mapped automatically. If the font name is unknown, please choose a different font from the font list.
+
+### Change Notes (No code change required)
+
+* `sleepOn()`, `sleepOff()`: supported, but better use `setPowerSave()`
+* `setColorIndex()` and `getColorIndex()` are renamed to `setDrawColor()` and 
+`getDrawColor()`. The old names are still supported.
+- `getFontAscent()` and `getFontDescent()` are renamed to `getAscent()` and `getDescent()`
+The old names are still supported.
+- Signal names are renamed in the constructor calls:
+
+| U8glib | U8g2 |
+| --- | --- |
+| U8glib sck | U8g2 clock |
+| U8glib mosi | U8g2 data |
+| U8glib a0 | U8g2 dc |
+
+- `getHeight()` renamed to `getDisplayHeight()`, old name still exists
+- `getWidth()` renamed to `getDisplayWidth()`, old name still exists