Legacy Document

Inside Macintosh: Text /

Chapter 3 - QuickDraw Text / QuickDraw Text Reference

Routines / Drawing Text

DrawText

The DrawText procedure draws the specified text at the current pen location in the current graphics port.

PROCEDURE DrawText (textBuf: Ptr; firstByte, byteCount: Integer);

textBuf

A pointer to a buffer containing the text to be drawn.

firstByte

An offset from the start of the text buffer (textBuf) to the first byte of the text to be drawn.

byteCount

The number of bytes of text to be drawn.

DESCRIPTION

The DrawText procedure draws the text with the leftmost glyph at the current pen location, extending right. After QuickDraw draws the text, it sets the pen location to the right of the rightmost glyph. For more information, see "Text Segments" on page 3-29.

Drawing text visible on the screen

QuickDraw temporarily stores on the stack all of the text you ask it to draw, even if the text is to be clipped. When drawing a range of text, it's best to draw only what is visible on the screen. If an entire text string does not fit on a line, truncate the text at a word boundary. If possible, avoid truncating within a style run. You can determine the number of characters whose glyphs actually fit on the screen by calling the TextWidth function before calling DrawText.

If you specify values in the graphics port spExtra and chExtra fields to change the width of nonspace and space characters, both TextWidth and DrawText take these values into account.

SPECIAL CONSIDERATIONS

For 1-byte complex script systems, DrawText substitutes the proper ligatures, reversals, and compound characters as needed.

For right-to-left text, such as Hebrew or Arabic, QuickDraw draws the final (leftmost) glyph first, then moves to the right through all the characters, drawing the initial (rightmost) glyph last.

For 2-byte script systems, note that byteCount is the number of bytes to be drawn, not the number of glyphs. Because 2-byte script systems also include characters consisting of only 1 byte, do not simply multiply the number of characters by 2 to determine this value; you must determine and specify the correct number of bytes.

Note

Inside a picture definition, DrawText cannot have a byteCount greater than 255.