Fix Graphics.createImage if the last character is a newline

            Graphics: Fix issue if drawImage given a non-image

ChangeLog

@@ -1,6 +1,8 @@
      2v19 : Fix Object.values/entries for numeric keys after 2v18 regression (fix #2375)
             nRF52: for SD>5 use static buffers for advertising and scan response data (#2367)
             Bangle.js: Add Bangle.showRecoveryMenu, and if storage is corrupt then show it rather than automatically doing factory reset
+            Fix Graphics.createImage if the last character is a newline
+            Graphics: Fix issue if drawImage given a non-image
 
      2v18 : Fix drawString with setClipRect with 90/270-degree rotation (fix #2343)
             Pico/Wifi: Enabled JIT compiler

libs/graphics/jswrap_graphics.c

@@ -789,15 +789,14 @@ JsVar *jswrap_graphics_createImage(JsVar *data) {
       } else {
         x=0;
         y++;
-        if (y>height) height=y;
+        if (y+1>height) height=y+1;
       }
     } else {
       x++;
       if (x>width) width=x;
     }
   }
-  if (x) height++;
-  if (height && ch=="\n") height--; // if the last char was a newline, ignore it
+  if (height && ch=='\n') height--; // if the last char was a newline, ignore it
   jsvStringIteratorFree(&it);
   // Sorted - now create the object, set it up and create the buffer
   JsVar *img = jsvNewObject();

src/jsvar.c

@@ -2249,6 +2249,7 @@ size_t jsvGetArrayBufferLength(const JsVar *arrayBuffer) {
 
 /** Get the String the contains the data for this arrayBuffer. Is ok with being passed a String in the first place. Offset is the offset in the backing string of this arraybuffer. */
 JsVar *jsvGetArrayBufferBackingString(JsVar *arrayBuffer, uint32_t *offset) {
+  if (!arrayBuffer) return 0;
   jsvLockAgain(arrayBuffer);
   if (offset) *offset = 0;
   while (jsvIsArrayBuffer(arrayBuffer)) {