Bugfix - Fix pallete size calculation (#87)

* Create cmake-multi-platform.yml

tryout1

* Update cmake-multi-platform.yml

* Update cmake-multi-platform.yml

* Update cmake-multi-platform.yml

* Update cmake-multi-platform.yml

* Update cmake-multi-platform.yml

* edited and renamed github action workflow file

* updated build definition

* fixing build definition

* Fixed calculation of palette size for most palletized bitmaps. 2^bitDepth instead of bitDepth*bitDepth. Calculation is needed because paletteSize in the DIB header is not filled correctly by the most image libs/tools, so 0 is read and calculation was wrong.

EleksTubeHAX_pio/src/TFTs.cpp

@@ -270,7 +270,7 @@ bool TFTs::LoadImageIntoBuffer(uint8_t file_index) {
   {
     read32(bmpFS); read32(bmpFS); read32(bmpFS); // size, w resolution, h resolution
     paletteSize = read32(bmpFS);
-    if (paletteSize == 0) paletteSize = bitDepth * bitDepth; // if 0, size is 2^bitDepth
+    if (paletteSize == 0) paletteSize = pow(2, bitDepth); // if 0, size is 2^bitDepth
     bmpFS.seek(14 + headerSize); // start of color palette
     for (uint16_t i = 0; i < paletteSize; i++) {
       palette[i] = read32(bmpFS);