/// <summary>
/// Get the bounding box internal text padding to be used when drawing text.
/// </summary>
public static User32.DRAWTEXTPARAMS GetTextMargins(
this FontCache.Scope font,
TextPaddingOptions padding = default)
{
// DrawText(Ex) adds a small space at the beginning of the text bounding box but not at the end,
// this is more noticeable when the font has the italic style. We compensate with this factor.
int leftMargin = 0;
int rightMargin = 0;
float overhangPadding;
switch (padding)
{
case TextPaddingOptions.GlyphOverhangPadding:
// [overhang padding][Text][overhang padding][italic padding]
overhangPadding = font.Data.Height / 6f;
leftMargin = (int)Math.Ceiling(overhangPadding);
rightMargin = (int)Math.Ceiling(overhangPadding * (1 + ItalicPaddingFactor));
break;
case TextPaddingOptions.LeftAndRightPadding:
// [2 * overhang padding][Text][2 * overhang padding][italic padding]
overhangPadding = font.Data.Height / 6f;
leftMargin = (int)Math.Ceiling(2 * overhangPadding);
rightMargin = (int)Math.Ceiling(overhangPadding * (2 + ItalicPaddingFactor));
break;
case TextPaddingOptions.NoPadding:
default:
break;
}
return(new User32.DRAWTEXTPARAMS
{
iLeftMargin = leftMargin,
iRightMargin = rightMargin
});
}
