Offline version of Online convert tools

These PHP scrips are the online converter tools:

• Image converter: https://littlevgl.com/image-to-c-array
• Font converter: https://littlevgl.com/ttf-font-to-c-array

Here you you can see how they work or download them to run offline.

Get started

This guide shows how to use the converters offline in a command line on Linux

1. Install PHP: sudo apt-get install php7.0-cli
2. Intall the Image manipulator extension for PHP: sudo apt-get install php7.0-gd
3. Clone or download the lv_utils repository: git clone https://github.com/littlevgl/lv_utils.git
4. Go to the lv_utils directory.

Run the Font converter offline

5. Copy a TTF file you want to use into the lv_utils directory
6. Run the script: php font_conv_core.php "name=arial_20&font=arial.ttf&height=20&bpp=4&uni_first=32&uni_last=126"
7. Chek the craeted C file in lv_utils directory.

The required arguments of the script:

• name name of the output file and font
• font name of font file to use (must be a *.ttf file)
• height desired height in px
• bpp Bit-per-pixel (1, 2, 4 or 8)
• uni_first the first unicode character to convert
• uni_last the ast unicode character to convert

Optional arguments:

• built_in convert a built in font with all bpp (0 or 1)
• list list of characters to include (must be in rango of uni_first and uni_last and in ascendant order). E.g. "list=123abc"
• scale scale up/down the letters [%] E.g. "scale=120"
• base_shift shift the base line [px] E.g. "base_shift=3"
• monospace use this fixed width [px] E.g. "monospace=12"

Example with all options

Convert only the numbers and + - sign with Arial font (The plus sign is replaced with %2B): php font_conv_core.php "name=arial_num_20&font=arial.ttf&height=20&bpp=8&uni_first=32&uni_last=126&list=%2B-0123456789&built_in=1"

Using the generated font in LittlevGL

• Copy the result C file into your LittlevGL project
• In a C file of your application declare the font as: extern lv_font_t my_font_name; or simply LV_FONT_DECLARE(my_font_name);
• Set the font in a style: style.text.font = &my_font_name;

Run the Image converter offline

5. Copy a BMP, JPG or PNG file you want to use into the lv_utils directory
6. Run the script: php img_conv_core.php "name=wallpaper&img=red_flower.png"
7. Chek the created C file in lv_utils directory.

The required arguments of the script:

• name name of the output file and image
• img an image file

Optional arguments:

• cf color format. Possible values are: true_color, true_color_alpha, true_color_chroma, indexed_1, indexed_2, indexed_4, indexed_8, alpha_1, alpha_2, alpha_4, alpha_8, raw, raw_alpha, raw_chroma. The default is: true_color.
• format C array or Binary output. Possible values are: c_array, bin_332, bin_565, bin_565_swap, bin_888. Default is: c_array.

Example with all options

Convert a bunny.png with alpha for all pixels to C array: php img_conv_core.php "name=icon&img=bunny.png&format=c_array&cf=alpha"

Using the generated image in LittlevGL

• For C arrays
  • Copy the result C file into your LittlevGL project
  • In a C file of your application declare the image as: extern const lv_img_t my_image_name; or LV_IMG_DECLARE(my_image_name);
  • Set the image for an lv_img object: lv_img_set_src(img1, &my_image_name);
• For externally binary files (e.g. SD card)
  • Set up a new driver. To learn more read the Tutorial.
  • Set the image for an lv_img object: lv_img_set_src(img1, "S:/path/to/image");

#Other offline tools

BDF Font Converter

utils/bdf_font_converter.py converts BDF files into a LittlevGL compatible c file. This converter is useful for generating pixel-perfect fonts, especially for monochrome displays. Help can be printed out by:

python bdf_font_converter.py --help

Typical use case (generates crox3hb.c):

python bdf_font_converter.py win_crox3hb.bdf crox3hb