Not working as expected

v_error_stbi_ttf_test.v

import os
import x.ttf
import stbi

fn main() {
    mut ttf_font := ttf.TTF_File{}
    ttf_font.buf = os.read_bytes('assets/fonts/ALS-Script.ttf') or { panic(err) }
    ttf_font.init()
    // print font info
    println(ttf_font.get_info_string())

    bmp_width := 200
    bmp_height := 64
    bmp_layers := 4 // number of planes for an RGBA buffer
    // memory size of the buffer
    bmp_size := bmp_width bmp_height * bmp_layers

    font_size := 32 // font size in points
    device_dpi := 72 // default screen DPI
    // Formula for scale calculation
    // scaler := (font_size * device dpi) / (72dpi * em_unit)
    scale := f32(font_size * device_dpi) / f32(72 * ttf_font.units_per_em)
    // height of the font to use in the buffer to separate the lines
    y_base := int((ttf_font.y_max - ttf_font.y_min) * scale)

    // declare the bitmap struct
    mut bmp := ttf.BitMap{
        tf: &ttf_font
        buf: unsafe { malloc(bmp_size) }
        buf_size: bmp_size
        width: bmp_width
        height: bmp_height
        bp: bmp_layers
        color: 0x000000_FF // RGBA black
        scale: scale
    }
    bmp.init_filler()
    bmp.clear()
    bmp.set_pos(10, y_base)
    bmp.draw_text('Test Text!')

    img := bmp.get_raw_bytes().data
    stbi.stbi_write_png('test.png', bmp_width, bmp_height, bmp_layers, img, bmp_width * bmp_layers)!
    stbi.stbi_write_jpg('test.jpg', bmp_width, bmp_height, bmp_layers, bmp.buf, 95)!
}