Added virtual (pure memory) display support

src/bb_ep.inl

@@ -1081,6 +1081,20 @@ int bbepSetPanelType(BBEPDISP *pBBEP, int iPanel)
     return BBEP_SUCCESS;
 } /* bbepSetPanelType() */
 
+int bbepCreateVirtual(BBEPDISP *pBBEP, int iWidth, int iHeight, int iFlags)
+{
+    if (pBBEP) {
+        memset(pBBEP, 0, sizeof(BBEPDISP));
+        pBBEP->native_width = pBBEP->width = iWidth;
+        pBBEP->native_height = pBBEP->height = iHeight;
+        pBBEP->iFlags = iFlags;
+        pBBEP->chip_type = BBEP_CHIP_NONE;
+        return BBEP_SUCCESS;
+    } else {
+        return BBEP_ERROR_BAD_PARAMETER;
+    }
+}
+
 //
 // Toggle the reset line to wake up the eink from deep sleep
 //

src/bb_epaper.cpp

@@ -105,7 +105,13 @@ int BBEPAPER::refresh(int iMode, bool bWait)
 //{
 //    _bbep.iFlags = iFlags;
 //}
-
+//
+// Create a RAM-only virtual display
+//
+int BBEPAPER::createVirtual(int iWidth, int iHeight, int iFlags)
+{
+    return bbepCreateVirtual(&_bbep, iWidth, iHeight, iFlags);
+}
 void BBEPAPER::setBuffer(uint8_t *pBuffer)
 {
     _bbep.ucScreen = pBuffer;

src/bb_epaper.h

@@ -58,6 +58,7 @@ enum {
     BBEP_CHIP_NOT_DEFINED = 0,
     BBEP_CHIP_SSD16xx,
     BBEP_CHIP_UC81xx,
+    BBEP_CHIP_NONE, // for virtual display
     BBEP_CHIP_COUNT
 };
 
@@ -285,6 +286,7 @@ class BBEPAPER
 {
   public:
     BBEPAPER(int iPanel);
+    int createVirtual(int iWidth, int iHeight, int iFlags);
     void setAddrWindow(int x, int y, int w, int h);
 #ifdef ARDUINO
     void initIO(int iDC, int iReset, int iBusy, int iCS = SS, int iMOSI = MOSI, int iSCLK = SCK, uint32_t u32Speed = 8000000);