Support converting 1- and 2-bit data to tiles

Author: Bim Overbohm

src/img2h.cpp

@@ -401,7 +401,16 @@ int main(int argc, const char *argv[])
                         imgSize = Magick::Geometry(8, 8);
                     }
                 }
-                nrOfBytesPerImageOrSprite = imgType == Magick::ImageType::PaletteType ? (maxColorMapColors <= 16 ? (nrOfBytesPerImageOrSprite / 2) : nrOfBytesPerImageOrSprite) : (nrOfBytesPerImageOrSprite * 2);
+                if (imgType == Magick::ImageType::PaletteType)
+                {
+                    nrOfBytesPerImageOrSprite = maxColorMapColors <= 16 ? (nrOfBytesPerImageOrSprite / 2) : nrOfBytesPerImageOrSprite;
+                    nrOfBytesPerImageOrSprite = maxColorMapColors <= 4 ? (nrOfBytesPerImageOrSprite / 2) : nrOfBytesPerImageOrSprite;
+                    nrOfBytesPerImageOrSprite = maxColorMapColors <= 2 ? (nrOfBytesPerImageOrSprite / 2) : nrOfBytesPerImageOrSprite;
+                }
+                else
+                {
+                    nrOfBytesPerImageOrSprite *= 2;
+                }
                 // convert image data to uint32_ts and palette to BGR555 uint16_ts
                 auto [imageData32, imageOrSpriteStartIndices] = Image::Processing::combineImageData<uint32_t>(images, options.interleavePixels);
                 // make sure we have the correct number of images. sprites and tiles will have no start indices, thus we need to use nrOfImagesOrSprites

src/processing/spritehelpers.cpp

@@ -32,7 +32,7 @@ std::vector<uint8_t> convertToWidth(const std::vector<uint8_t> &src, uint32_t wi
 std::vector<uint8_t> convertToTiles(const std::vector<uint8_t> &src, uint32_t width, uint32_t height, uint32_t bitsPerPixel, uint32_t tileWidth, uint32_t tileHeight)
 {
     bitsPerPixel = bitsPerPixel == 15 ? 16 : bitsPerPixel;
-    REQUIRE(bitsPerPixel == 4 || bitsPerPixel == 8 || bitsPerPixel == 16, std::runtime_error, "Bits per pixel must be in [4, 8, 15, 16]");
+    REQUIRE(bitsPerPixel == 1 || bitsPerPixel == 2 || bitsPerPixel == 4 || bitsPerPixel == 8 || bitsPerPixel == 16, std::runtime_error, "Bits per pixel must be in [1, 2, 4, 8, 15, 16]");
     REQUIRE(tileWidth % 8 == 0 && tileHeight % 8 == 0, std::runtime_error, "Tile width and height must be divisible by 8");
     REQUIRE(width % 8 == 0 && height % 8 == 0, std::runtime_error, "Width and height must be divisible by 8");
     std::vector<uint8_t> dst(src.size());