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NChar2Pixel

Find screen position of carets and selection points

#include <Script.h> Script Manager

short NChar2Pixel(textBuf, textLen, slop, offset, direction,

styleRunPosition, numer, denom );

Ptr textBuf ; address of a text buffer

long textLen ; value for text length

Fixed slop ; value indicating extra pixels

long offset; nearest character offset

short direction; indicates direction script is written

JustStyleCode styleRunPosition ; the position of a style run within the line

Point numer ; scaling factor

Point denom ; scaling factor

NChar2Pixel finds the screen position of carets and selection points, given

the text buffer and an offset. NChar2Pixel is the inverse of NPixel2Char.

For left-to-right scripts (including Kanji), this function works the same way

as the TextWidth function in QuickDraw. This is a more powerful version

of Char2Pixel that works with intercharacter spacing, lets you indicate the

position of a style run within a line for lines with multiple style runs, and

accepts scaling parameters.

textBuf is a text buffer indicated by a pointer.

textLen is the length of the specified string.

slop is the number of pixels to add to a string's width after it has been

scaled. For unjustified text pass 0.

offset is an integer that is the nearest character offset within the text

buffer corresponding to a given pixel width.

direction indicates if the script is written left-to- right, or otherwise. The

following pre defined constants are available for direction:

smLeftCaret = 0 place caret for left block

smRightCaret = -1 place caret for right block

smHilite = 1 direction is TESysJust

styleRunPosition For correct spacing between multiple style runs, you can specify

the position of a style run within the line by using the

styleRunPosition parameter of type JustStyleCode. See below for a

list of the values and meanings for these constants.

numer is a scaling factor

denom is a scaling factor

Returns: a short, whose value indicates the screen position of carets and

selection points.

Notes: To handle the spacing between multiple style runs on a line correctly, the

new justification routines take a styleRunPosition parameter that specifies

the position of the style run on a line.

The values for styleRunPosition are as follows:

Constant Meaning

smOnlyStyleRun This style run is the only one on the line.

smLeftStyleRun Multiple style runs are on the line, and this is the

leftmost.

smRightStyleRun Multiple style runs are on the line, and this is the

rightmost.

smMiddleStyleRun Multiple style runs are on the line, and this is

neither the leftmost nor the rightmost.

If styleRunPosition has the value smOnlyStyleRun, the justification

routines behave exactly like their earlier versions. For other values of

styleRunPosition, the behavior may depend on the script. The behavior for

Roman is in Justifying Text on the Roman Script System.

Note: In the NMeasureJust, NChar2Pixel, and NPixel2Char

routines, the text length should equal the entire visible part of the

style run on a line and should include trailing spaces if and only if

they are displayed. (They may not be displayed for the last style run

in the line, for example.) Otherwise, the results for the last

character on the line may be in valid.

Referenced by (8):