x>offset ( x font string -- n )
Factor handbook » UI framework » Implementing new gadgets » Customizing gadget appearance » Implementing custom drawing logic » Rendering text

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Vocabulary
ui.text

Inputs

x	a real
font	a font
string	a string

Outputs

n	an integer

Generic word contract
Outputs the string index closest to the given x coordinate.

Definition

USING: ui.text.private ;

IN: ui.text

HOOK: x>offset font-renderer ( x font string -- n )

Methods

USING: accessors core-graphics.types core-text
io.encodings.string io.encodings.utf16 kernel math opengl
sequences ui.text ui.text.core-text ;

M:: core-text-renderer x>offset ( x font string -- n )
    x font string
    [ 2drop 0 ] [
        cached-line line>> swap gl-scale 0 <CGPoint>
        CTLineGetStringIndexForPosition 2 *
        0 swap string utf16n encode subseq utf16n decode length
    ] if-empty ;