draw.py 文件源码

def gradientLine( ctx, points_list, hsl_palette_list, loop_palette = True ):
    pal = hsl_palette_list[:]
    if loop_palette:
        pal.append( hsl_palette_list[0] ) # Duplicate first

    rgb = Colz.hslToRgb( *pal[0] )
    ctx.set_source_rgb( *rgb )

    for i in range( 2, len(points_list), 2 ):
        pal_pos = i * ( len(pal) - 1 ) / len(points_list)
        col_current = math.floor( pal_pos )
        col_next = math.ceil( pal_pos )
        frac, whole = math.modf( pal_pos )
        if col_current == col_next:
            col_next = min( col_current + 1, len(pal) - 1 )
        c_mix = Colz.interpolate( pal[col_current], pal[col_next], frac )

        ctx.set_source_rgb( *c_mix.rgb )
        ctx.move_to( points_list[i-2], points_list[i-1] )
        ctx.line_to( points_list[i], points_list[i+1] )
        ctx.stroke()

# Pass caito ctx, list of points, list of colors ( colz )