Remove dependency

DEVELOPER.md

@@ -25,7 +25,6 @@ Install these:
 * Docker Compose
 * jq
 * curl
-* ImageMagick
 * ffmpeg
 
 Then run this:

test/util/rand-image.sh

@@ -0,0 +1,90 @@
+raw_rand_bmp () {
+  local width=$1
+  local height=$2
+
+  # Each row is width*3 bytes (24-bit = 3 bytes/pixel),
+  # then padded to a multiple of 4.
+  local row_size=$(( (width * 3 + 3) & ~3 ))
+  local pixel_data_size=$((row_size * height))
+  local file_size=$((54 + pixel_data_size))
+
+  # ----------------------------------------------------------------------------
+  # 1) BMP FILE HEADER (14 bytes)
+  # ----------------------------------------------------------------------------
+  # - Signature "BM" (2 bytes)
+  printf "BM"
+
+  # - File size (4 bytes, little-endian)
+  printf "\\x$(printf '%02x' $((file_size       & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((file_size >> 8) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((file_size >>16) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((file_size >>24) & 0xFF)))"
+
+  # - Reserved1 (2 bytes) = 0
+  printf "\\x00\\x00"
+
+  # - Reserved2 (2 bytes) = 0
+  printf "\\x00\\x00"
+
+  # - Offset to start of pixel data (4 bytes) = 54 decimal = 0x36
+  #   (14-byte file header + 40-byte DIB header)
+  printf "\\x36\\x00\\x00\\x00"
+
+  # ----------------------------------------------------------------------------
+  # 2) DIB HEADER: BITMAPINFOHEADER (40 bytes)
+  # ----------------------------------------------------------------------------
+  # - Header size (4 bytes) = 40
+  printf "\\x28\\x00\\x00\\x00"
+
+  # - Width (4 bytes, little-endian)
+  printf "\\x$(printf '%02x' $(( width       & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((width >> 8) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((width >>16) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((width >>24) & 0xFF)))"
+
+  # - Height (4 bytes, little-endian)
+  #   Note: BMP stores rows from bottom to top if height is positive
+  printf "\\x$(printf '%02x' $(( height       & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((height >> 8) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((height >>16) & 0xFF)))"
+  printf "\\x$(printf '%02x' $(((height >>24) & 0xFF)))"
+
+  # - Planes (2 bytes) = 1
+  printf "\\x01\\x00"
+
+  # - Bits per pixel (2 bytes) = 24
+  printf "\\x18\\x00"
+
+  # - Compression (4 bytes) = 0 (BI_RGB)
+  printf "\\x00\\x00\\x00\\x00"
+
+  # - Image size (4 bytes) = 0 for uncompressed BI_RGB
+  printf "\\x00\\x00\\x00\\x00"
+
+  # - X pixels per meter (4 bytes) = 0 (you can put 2835 for ~72 DPI)
+  printf "\\x00\\x00\\x00\\x00"
+
+  # - Y pixels per meter (4 bytes) = 0
+  printf "\\x00\\x00\\x00\\x00"
+
+  # - Total colors (4 bytes) = 0
+  printf "\\x00\\x00\\x00\\x00"
+
+  # - Important colors (4 bytes) = 0
+  printf "\\x00\\x00\\x00\\x00"
+
+  # ----------------------------------------------------------------------------
+  # 3) Pixel data (BGR, bottom-to-top). But random is fine either way.
+  # ----------------------------------------------------------------------------
+  #
+  # We only need "row_size * height" bytes. We'll read that many from /dev/urandom.
+  # That automatically includes the per-row padding. (We don't have to do anything special
+  # as long as we read the right total number of bytes.)
+  #
+  # Because the BMP spec says rows are in bottom-to-top order, each row is
+  # actually the last row in the file. But for random data, it makes no difference.
+  #
+  dd if=/dev/urandom bs="${pixel_data_size}" count=1 2>/dev/null
+}
+
+raw_rand_bmp "$@"

test/util/setup.sh

@@ -143,25 +143,7 @@ j_assert_length () {
 }
 
 rand_image () {
-  local characters=({a..z} {A..Z} {0..9})
-
-  # Generate a random index for letter
-  local index=$(($RANDOM % ${#characters[@]}))
-
-  # Generate a random color for the background
-  local rand_color=$(
-    printf "%02x%02x%02x\n" \
-      $(($RANDOM % 256)) \
-      $(($RANDOM % 256)) \
-      $(($RANDOM % 256))
-  )
-
-  # Create an image with a random letter, a random background color, and a shadow,
-  # then output it to stdout and pipe through base64
-  convert -size 400x400 xc:"#${rand_color}" -gravity center -pointsize 320 \
-      -fill black -annotate +10+10 "${characters[$index]}" \
-      -fill white -annotate +0+0 "${characters[$index]}" \
-      png:- | base64 -w 0
+  ./rand-image.sh 200 200 | base64 -w 0
 }
 
 rand_sound () {