.\" Copyright (c) 2002-2023 Julien Nadeau Carriere .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, .\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES .\" (INCLUDING BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR .\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING .\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .Dd December 21, 2022 .Dt AG_LABEL 3 .Os Agar 1.7 .Sh NAME .Nm AG_Label .Nd agar label widget .Sh SYNOPSIS .Bd -literal #include #include .Ed .Sh DESCRIPTION .\" IMAGE(/widgets/AG_Label.png, "Two AG_Labels") The .Nm widget displays single-line or multi-line text. It supports static labels as well as .Em polled labels (labels containing dynamically-updated data which will be dereferenced on rendering). .Sh INHERITANCE HIERARCHY .Xr AG_Object 3 -> .Xr AG_Widget 3 -> .Nm . .Sh INITIALIZATION .nr nS 1 .Ft "AG_Label *" .Fn AG_LabelNew "AG_Widget *parent" "Uint flags" "const char *fmt" "..." .Pp .Ft "AG_Label *" .Fn AG_LabelNewS "AG_Widget *parent" "Uint flags" "const char *text" .Pp .Ft "AG_Label *" .Fn AG_LabelNewPolled "AG_Widget *parent" "Uint flags" "const char *fmt" "..." .Pp .Ft "AG_Label *" .Fn AG_LabelNewPolledMT "AG_Widget *parent" "Uint flags" "AG_Mutex *mutex" "const char *fmt" "..." .Pp .Ft void .Fn AG_LabelText "AG_Label *label" "const char *format" "..." .Pp .Ft void .Fn AG_LabelTextS "AG_Label *label" "const char *s" .Pp .Ft void .Fn AG_LabelAppend "AG_Label *label" "const char *format" "..." .Pp .Ft void .Fn AG_LabelAppendS "AG_Label *label" "const char *s" .Pp .Ft "void" .Fn AG_LabelSetFont "AG_Label *label" "AG_Font *font" .Pp .Ft "void" .Fn AG_LabelSetColor "AG_Label *label" "AG_Color C" .Pp .Ft "void" .Fn AG_LabelSetColorBG "AG_Label *label" "AG_Color C" .Pp .Ft "void" .Fn AG_LabelSetPadding "AG_Label *label" "int left" "int right" "int top" "int bottom" .Pp .Ft "void" .Fn AG_LabelJustify "AG_Label *label" "enum ag_text_justify justify" .Pp .Ft "void" .Fn AG_LabelValign "AG_Label *label" "enum ag_text_valign valign" .Pp .Ft "void" .Fn AG_LabelSizeHint "AG_Label *label" "Uint nlines" "const char *text" .Pp .nr nS 0 The .Fn AG_LabelNew function allocates, initializes and attaches a .Nm widget initially displaying the given text. .Pp The .Fn AG_LabelNewPolled function creates a new .Nm widget displaying a string of text which contains references to variables. The .Fn AG_LabelNewPolledMT variant accepts a pointer to a mutex that will be automatically acquired and release as the widget accesses the referenced data. See the .Sx POLLED LABELS section for more details. .Pp See .Sx LABEL FLAGS section for a the accepted .Fa flags values for .Fn AG_LabelNew and .Fn AG_LabelNewPolled . .Pp .Fn AG_LabelText changes the text contents of the label to the given string. .Fn AG_LabelAppend appends the given string to the existing text. .Pp The .Fn AG_LabelSetFont function configures an alternate font which will be used to display the label. The .Fa font argument is not duplicated (i.e., the referenced font should remain valid as long as the widget exists). To set the font of a label back to the default Agar font, NULL can be passed. See .Xr AG_FetchFont 3 for details on Agar fonts. .Pp .Fn AG_LabelSetColor and .Fn AG_LabelSetColorBG configure an alternate text and background color for the label (see .Xr AG_Color 3 ) . .Pp .Fn AG_LabelSetPadding sets the label padding parameters in pixels. If a parameter is -1, its current value is preserved. .Pp The .Fn AG_LabelJustify function sets the text justification: .Bd -literal .\" SYNTAX(c) enum ag_text_justify { AG_TEXT_LEFT, AG_TEXT_CENTER, AG_TEXT_RIGHT }; .Ed .Pp .Fn AG_LabelValign sets the vertical text alignment: .Bd -literal .\" SYNTAX(c) enum ag_text_valign { AG_TEXT_TOP, AG_TEXT_MIDDLE, AG_TEXT_BOTTOM }; .Ed .Pp The .Fn AG_LabelSizeHint function arranges for the minimum scaling of the label to accomodate at least .Fa nlines lines of the given text string. If .Fa nlines is 0, the number of lines will be based on the contents of the text string. .Sh POLLED LABELS .Fn AG_LabelNewPolled and .Fn AG_LabelNewPolledMT may be used to display a label containing dynamically accessed elements (i.e., the actual string will be compiled on rendering). .Fn AG_LabelNewPolled accepts an Agar-style format string (see .Xr AG_String 3 for details). Subsequent arguments must be pointers (as opposed to literal data), and the formatting engine also provides Agar-specific extensions. .Sh EVENTS The .Nm widget does not generate any event. .Sh LABEL FLAGS The following .Nm .Fa flags are defined: .Bl -tag -width "AG_LABEL_PARTIAL " .It AG_LABEL_FRAME Draw a visible frame around the label. .It AG_LABEL_PARTIAL The label is partially hidden (read-only). .It AG_LABEL_REGEN Force re-rendering of the text at next draw (used internally by .Fn AG_LabelString , etc.) .It AG_LABEL_SLOW Update polled labels every 2s (as opposed to 500ms). .It AG_LABEL_HFILL Expand horizontally in parent container. .It AG_LABEL_VFILL Expand vertically in parent container. .It AG_LABEL_EXPAND Shorthand for .Dv AG_LABEL_HFILL | AG_LABEL_VFILL . .El .Sh EXAMPLES The following code snippet creates a window containing both a static label and a polled label: .Bd -literal -offset indent .\" SYNTAX(c) AG_Window *win; int myInt = 1234; AG_Label *myLbl; win = AG_WindowNew(0); AG_LabelNew(win, 0, "Foo"); myLbl = AG_LabelNewPolled(win, 0, "myInt=%i", &myInt); AG_LabelSizeHint(myLbl, 1, "myInt=0000"); .Ed .Pp Thread-safe code can associate polled labels with mutexes protecting the data to access: .Bd -literal -offset indent .\" SYNTAX(c) int myInt = 1234; AG_Mutex myMutex = AG_MUTEX_INITIALIZER; AG_LabelNewPolledMT(win, 0, &myMutex, "myInt=%i", &myInt); .Ed .Pp The following code fragment defines a custom format specifier, which can be used in polled labels (and is also recognized by .Fn AG_Printf ) . For more details on custom format specifiers, refer to .Xr AG_String 3 . .Bd -literal -offset indent .\" SYNTAX(c) AG_Size PrintMyVector(AG_FmtString *fs, char *dst, AG_Size dstSize) { struct my_vector *my = AG_LABEL_ARG(fs); return AG_Snprintf(dst, dstSize, "[%f,%f]", my->x, my->y); } .Li ... struct my_vector v; AG_RegisterFmtStringExt("myVec", PrintMyVector); AG_LabelNewS(parent, 0, "Static label: %[myVec]", &v); AG_LabelNewPolled(parent, 0, "Polled label: %[myVec]", &v); .Ed .Sh SEE ALSO .Xr AG_FetchFont 3 , .Xr AG_Intro 3 , .Xr AG_Pixmap 3 , .Xr AG_String 3 , .Xr AG_Widget 3 , .Xr AG_Window 3 .Sh HISTORY The .Nm widget first appeared in Agar 1.0. In Agar 1.5.0, the formatting engine which implements polled labels was rewritten and generalized. The .Fn AG_LabelAppend function appeared in Agar 1.7.0.