// Set up the drawingwand "dw" for the given font name, font size, and colour.
// If the font or size changes sx get the new width of a space
// (the magickwand is required if it is necessary to query the font metrics)
func draw_setfont(mw *imagick.MagickWand, dw *imagick.DrawingWand, font string, size float64, colour string, sx *float64) {
sflag := false
if len(font) > 0 {
dw.SetFont(font)
sflag = true
}
if len(colour) > 0 {
pw := imagick.NewPixelWand()
pw.SetColor(colour)
dw.SetFillColor(pw)
pw.Destroy()
sflag = true
}
if size > 0 {
dw.SetFontSize(size)
}
// If either the font or the fontsize (or both) have changed
// we need to get the size of a space again
if sflag {
fm := mw.QueryFontMetrics(dw, " ")
*sx = fm.TextWidth
}
}
// The easiest (?) way to handle vertical text placement is
// not to use gravity at all because then you know that all the text is
// placed relative to ImageMagick's (0,0) coordinate which is the top left of
// the screen and the baseline will be y=0.
func draw_metrics(mw *imagick.MagickWand, dw *imagick.DrawingWand, dx *float64, dy, sx float64, text string) {
mw.AnnotateImage(dw, *dx, dy, 0, text)
mw.DrawImage(dw)
// get the font metrics
fm := mw.QueryFontMetrics(dw, text)
if fm != nil {
// Adjust the new x coordinate
*dx += fm.TextWidth + sx
}
}