Improve docs and add two new Fl_Menu_Item methods (#875)
This addresses some issues pointed out by GitHub Issue #875. Documentation lacked details about Fl_Multi_Label assignment and correct memory handling. The new methods - Fl_Menu_Item::image_label(const Fl_Image *) and - Fl_Menu_Item::multi_label(const Fl_Multi_Label *) provide a cleaner interface to assign images and Fl_Multi_Label's to menu items. examples/howto-menu-with-images.cxx: carify some issues, fix leak, and use new Fl_Menu_Item::multi_label(const Fl_Multi_Label *).
This commit is contained in:
Albrecht Schlosser
parent
016c36c917
commit
1d73c0195c
@ -17,9 +17,10 @@
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#ifndef Fl_Menu_Item_H
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#define Fl_Menu_Item_H
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# include "Fl_Widget.H"
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# include "Fl_Image.H"
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# include <FL/platform_types.h> // for FL_COMMAND and FL_CONTROL
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#include <FL/Fl_Widget.H>
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#include <FL/Fl_Image.H>
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#include <FL/Fl_Multi_Label.H>
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#include <FL/platform_types.h> // for FL_COMMAND and FL_CONTROL
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// doxygen needs the following line to enable e.g. ::FL_MENU_TOGGLE to link to the enums
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/// @file
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@ -141,19 +142,100 @@ struct FL_EXPORT Fl_Menu_Item {
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// methods on menu items:
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/**
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Returns the title of the item.
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Returns the title (label) of the menu item.
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A NULL here indicates the end of the menu (or of a submenu).
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A '&' in the item will print an underscore under the next letter,
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and if the menu is popped up that letter will be a "shortcut" to pick
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that item. To get a real '&' put two in a row.
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and if the menu is popped up that letter will be a "shortcut" to
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pick that item. To get a real '&' put two in a row.
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The returned value depends on the labeltype() that has been used
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to store the label.
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\returns A pointer to the label cast to (const char *)
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\retval (a) A pointer to text (const char *)
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\retval (b) A pointer to an image (Fl_Image *)
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\retval (c) A pointer to a "multi label" (Fl_Multi_Label *)
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\retval NULL End of menu or submenu
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\see Fl_Menu_Item::label(const char *)
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\see Fl_Menu_Item::label(Fl_Labeltype, const char *)
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\see Fl_Menu_Item::image_label(const Fl_Image *)
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\see Fl_Menu_Item::multi_label(const Fl_Multi_Label *)
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\see Fl_Multi_Label::label(Fl_Menu_Item *)
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*/
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const char* label() const {return text;}
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const char* label() const { return text; }
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/** See const char* Fl_Menu_Item::label() const */
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void label(const char* a) {text=a;}
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/**
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Sets the title (label) of the menu item.
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/** See const char* Fl_Menu_Item::label() const */
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void label(Fl_Labeltype a,const char* b) {labeltype_ = a; text = b;}
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\note This does \b not change the labeltype() for backwards compatibility.
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Take care to assign the correct labeltype() if you assign different
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label types to the same menu item sequentially.
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The default labeltype() is FL_NORMAL_LABEL.
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\see label(Fl_Labeltype, const char*)
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\see const char* Fl_Menu_Item::label() const
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*/
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void label(const char* a) { text = a; }
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/**
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Sets the title (label) and the label type of the menu item.
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The default Fl_Labeltype when using Fl_Menu_Item::label(const char* a)
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is FL_NORMAL_LABEL but you can set any other label type, for instance
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FL_EMBOSSED_LABEL.
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Special labeltypes are:
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- FL_ICON_LABEL: draws the icon (Fl_Image) associated with the text
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- FL_IMAGE_LABEL: draws the image (Fl_Image) associated with the text
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- FL_MULTI_LABEL: draws multiple parts side by side, see Fl_Multi_Label
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\see const char* Fl_Menu_Item::label() const
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*/
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void label(Fl_Labeltype a, const char* b) {
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labeltype_ = a;
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text = b;
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}
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/**
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Sets the title (label()) and labeltype() to an Fl_Multi_Label.
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This sets the labeltype() to \_FL_MULTI_LABEL (note the leading
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underscore).
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\see const char* Fl_Menu_Item::label() const
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\since 1.4.0
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\internal Overloading Fl_Menu_Item::image() would lead to ambiguities
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when used like `item->label(0)`, hence we need our own method name.
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Otherwise existing programs might not compile w/o error (e.g. fluid).
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*/
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void multi_label(const Fl_Multi_Label *ml) {
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label(FL_MULTI_LABEL, (const char *)ml);
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}
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/**
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Sets the title (label()) to an icon or image.
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This sets the labeltype() to \_FL_IMAGE_LABEL (note the leading
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underscore).
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\see const char* Fl_Menu_Item::label() const
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\since 1.4.0
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\internal Overloading Fl_Menu_Item::image() would lead to ambiguities
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when used like `item->label(0)`, hence we need our own method name.
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Otherwise existing programs might not compile w/o error (e.g. fluid).
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*/
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void image_label(const Fl_Image *image) {
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label(FL_IMAGE_LABEL, (const char *)image);
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}
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/**
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Returns the menu item's labeltype.
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@ -1,7 +1,7 @@
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//
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// Multi-label header file for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2015 by Bill Spitzak and others.
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// Copyright 1998-2023 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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@ -22,51 +22,57 @@ struct Fl_Menu_Item;
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/** Allows a mixed text and/or graphics label to be applied to an Fl_Menu_Item or Fl_Widget.
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Most regular FLTK widgets now support the ability to associate both images and text
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with a label but some special cases, notably the non-widget Fl_Menu_Item objects, do not.
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Fl_Multi_Label may be used to create menu items that have an icon and text, which would
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not normally be possible for an Fl_Menu_Item.
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For example, Fl_Multi_Label is used in the New->Code submenu in fluid, and others.
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Most regular FLTK widgets now support the ability to associate both images and text
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with a label but some special cases, notably the non-widget Fl_Menu_Item objects, do not.
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Fl_Multi_Label may be used to create menu items that have an icon and text, which would
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not normally be possible for an Fl_Menu_Item.
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For example, Fl_Multi_Label is used in the New->Code submenu in fluid, and others.
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\image html Fl_Multi_Label-menu-item.png "Menu items with icons using Fl_Multi_Label"
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\image latex Fl_Multi_Label-menu-item.png "Menu items with icons using Fl_Multi_Label" width=4cm
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\image html Fl_Multi_Label-menu-item.png "Menu items with icons using Fl_Multi_Label"
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\image latex Fl_Multi_Label-menu-item.png "Menu items with icons using Fl_Multi_Label" width=4cm
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Each Fl_Multi_Label holds two elements, labela and labelb; each may hold either a
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text label (const char*) or an image (Fl_Image*). When displayed, labela is drawn first
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and labelb is drawn immediately to its right.
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Each Fl_Multi_Label holds two elements, \p labela and \p labelb; each may hold either a
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text label (const char*) or an image (Fl_Image*). When displayed, \p labela is drawn first
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and \p labelb is drawn immediately to its right.
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More complex labels might be constructed by setting labelb as another Fl_Multi_Label and
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thus chaining up a series of label elements.
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More complex labels can be constructed by setting labelb as another Fl_Multi_Label and
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thus chaining up a series of label elements.
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When assigning a label element to one of labela or labelb, they should be explicitly cast
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to (const char*) if they are not of that type already.
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When assigning a label element to one of \p labela or \p labelb, they should be
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explicitly cast to (const char*) if they are not of that type already.
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Example Use: Fl_Menu_Bar
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\code
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Fl_Pixmap *image = new Fl_Pixmap(..); // image for menu item; any Fl_Image based widget
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Fl_Menu_Bar *menu = new Fl_Menu_Bar(..); // can be any Fl_Menu_ oriented widget (Fl_Choice, Fl_Menu_Button..)
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\note An Fl_Multi_Label object and all its components (label text, images, chained
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Fl_Multi_Label's and their linked objects) must exist during the lifetime of the
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widget or menu item they are assigned to. It is the responsibility of the user's
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code to release these linked objects if necessary after the widget or menu is deleted.
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// Create a menu item
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int i = menu->add("File/New", ..);
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Fl_Menu_Item *item = (Fl_Menu_Item*)&(menu->menu()[i]);
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Example Use: Fl_Menu_Bar
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\code
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Fl_Pixmap *image = new Fl_Pixmap(..); // image for menu item; any Fl_Image based widget
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Fl_Menu_Bar *menu = new Fl_Menu_Bar(..); // can be any Fl_Menu_ oriented widget (Fl_Choice, Fl_Menu_Button..)
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// Create a multi label, assign it an image + text
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Fl_Multi_Label *ml = new Fl_Multi_Label;
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// Create a menu item
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int i = menu->add("File/New", ..);
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Fl_Menu_Item *item = (Fl_Menu_Item*)&(menu->menu()[i]);
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// Left side of label is an image
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ml->typea = FL_IMAGE_LABEL;
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ml->labela = (const char*)image; // any Fl_Image widget: Fl_Pixmap, Fl_PNG_Image, etc..
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// Create a multi label, assign it an image + text
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Fl_Multi_Label *ml = new Fl_Multi_Label;
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// Right side of label is label text
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ml->typeb = FL_NORMAL_LABEL;
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ml->labelb = item->label();
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// Left side of label is an image
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ml->typea = FL_IMAGE_LABEL;
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ml->labela = (const char*)image; // any Fl_Image widget: Fl_Pixmap, Fl_PNG_Image, etc..
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// Assign the multilabel to the menu item
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ml->label(item);
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\endcode
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// Right side of label is label text
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ml->typeb = FL_NORMAL_LABEL;
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ml->labelb = item->label();
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\see Fl_Label and Fl_Labeltype and examples/howto-menu-with-images.cxx
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*/
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// Assign the multilabel to the menu item
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// ml->label(item); // deprecated since 1.4.0; backwards compatible with 1.3.x
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item->label(ml); // new method since 1.4.0
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\endcode
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\see Fl_Label and Fl_Labeltype and examples/howto-menu-with-images.cxx
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*/
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struct FL_EXPORT Fl_Multi_Label {
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/** Holds the "leftmost" of the two elements in the composite label.
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Typically this would be assigned either a text string (const char*),
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@ -87,9 +93,10 @@ struct FL_EXPORT Fl_Multi_Label {
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if "chaining" multiple Fl_Multi_Label elements together. */
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uchar typeb;
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/** This method is used to associate a Fl_Multi_Label with a Fl_Widget. */
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// This method is used to associate a Fl_Multi_Label with a Fl_Widget.
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void label(Fl_Widget*);
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/** This method is used to associate a Fl_Multi_Label with a Fl_Menu_Item. */
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// This method is used to associate a Fl_Multi_Label with a Fl_Menu_Item.
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void label(Fl_Menu_Item*);
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};
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@ -1,10 +1,8 @@
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//
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// vim: autoindent tabstop=2 shiftwidth=2 expandtab softtabstop=2 filetype=cpp
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//
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// How to use Fl_Multi_Label to make menu items with images and labels.
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// How to use Fl_Multi_Label to make menu items with images and labels.
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//
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// Copyright 2017 Greg Ercolano.
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// Copyright 1998-2021 by Bill Spitzak and others.
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// Copyright 1998-2023 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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@ -28,6 +26,8 @@
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#include <FL/Fl_Pixmap.H>
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#include <FL/fl_message.H>
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#include <stdlib.h> // free()
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// Document icon
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static const char *L_document_xpm[] = {
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"13 11 3 1",
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@ -120,14 +120,20 @@ int AddItemToMenu(Fl_Menu_ *menu, // menu to add item to
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// Right side of label is text
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ml->typeb = FL_NORMAL_LABEL;
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ml->labelb = item->label();
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ml->labelb = item->label(); // transfers "ownership" to ml
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// Assign multilabel to item.
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// Note: There are two documented ways to achieve this. Both of them
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// are supported, but one of them is commented out intentionally.
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// There are three documented ways to achieve this. All of them are still
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// supported but two of them are deprecated (see docs and comments below).
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// The recommended way is to use Fl_Menu_Item::multi_label(Fl_Multi_Label *)
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// which was added in FLTK 1.4.0 and sets the correct labeltype().
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// All of these statements overwrite the old label (pointer) whose
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// ownership has been "transferred" to the Fl_Multi_Label (correct).
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// The old label is not released (as documented).
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// item->label(FL_MULTI_LABEL, (const char *)ml);
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ml->label(item);
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// ml->label(item); // deprecated (1.3.x)
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// item->label(FL_MULTI_LABEL, (const char *)ml); // deprecated (1.3.x)
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item->multi_label(ml); // new since 1.4.0
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return i;
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}
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@ -151,29 +157,37 @@ void CreateMenuItems(Fl_Menu_* menu) {
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// This shows why you need Fl_Multi_Label; the item->label()
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// gets clobbered by the item->image() setting.
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//
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// In the following lines 'menu->add(...)' assigns a duplicated label
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// string which must be released prior to assigning an image to the label
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// with 'item->image()'.
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// This is "not nice" but it prevents memory leaks (see GitHub Issue #875).
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int i;
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Fl_Menu_Item *item;
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i = menu->add("Images/One", 0, Menu_CB, (void*)"One");
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item = (Fl_Menu_Item*)&(menu->menu()[i]);
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item->image(L_document_pixmap); // note: this clobbers the item's label()
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free((void*)item->label());
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item->image(L_document_pixmap);
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i = menu->add("Images/Two", 0, Menu_CB, (void*)"Two");
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item = (Fl_Menu_Item*)&(menu->menu()[i]);
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free((void*)item->label());
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item->image(L_folder_pixmap);
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i = menu->add("Images/Three", 0, Menu_CB, (void*)"Three");
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item = (Fl_Menu_Item*)&(menu->menu()[i]);
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free((void*)item->label());
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item->image(L_redx_pixmap);
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}
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int main() {
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int main(int argc, char **argv) {
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Fl_Double_Window *win = new Fl_Double_Window(400, 400, "Menu items with images");
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win->tooltip("Right click on window background\nfor popup menu");
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// Help message
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Fl_Box *box = new Fl_Box(100,100,200,200);
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box->copy_label(win->tooltip());
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box->label(win->tooltip()); // no need to copy_label() because it's static
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box->align(FL_ALIGN_CENTER|FL_ALIGN_INSIDE);
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// Menu bar
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@ -192,12 +206,11 @@ int main() {
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// TODO: Show complex labels with Fl_Multi_Label. From docs:
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//
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// "More complex labels might be constructed by setting labelb as another
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// "More complex labels can be constructed by setting labelb as another
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// Fl_Multi_Label and thus chaining up a series of label elements."
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//
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win->end();
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win->resizable(win);
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win->show();
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win->show(argc, argv);
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return Fl::run();
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}
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@ -1,7 +1,7 @@
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//
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// Multi-label widget for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2017 by Bill Spitzak and others.
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// Copyright 1998-2023 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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@ -60,10 +60,63 @@ Fl_Labeltype fl_define_FL_MULTI_LABEL() {
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return _FL_MULTI_LABEL;
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}
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/**
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Associate an Fl_Multi_Label with an Fl_Widget.
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This method uses Fl_Widget::label(Fl_Labeltype, const char *) internally
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to set the \e label of the widget, i.e. it stores a \e pointer to the
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Fl_Multi_Label object (\e this).
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An existing label that has been set using Fl_Widget::copy_label() will be
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released prior to the assignment of the new label.
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This sets the type of the widget's label to \_FL_MULTI_LABEL - note the
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leading underscore ('_').
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There is no way to use a method like Fl_Widget::copy_label() that transfers
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ownership of the Fl_Multi_Label and its linked objects (images, text, and
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chained Fl_Multi_Label's) to the widget.
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The Fl_Multi_Label and all linked images, text labels, or chained Fl_Multi_Label
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objects must exist during the lifetime of the widget and will not be released
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when the widget is destroyed.
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\note The user's code is responsible for releasing the Fl_Multi_Label and
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all linked objects (images, text, chained Fl_Multi_Label's) after the
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widget has been deleted. This may cause memory leaks if Fl_Multi_Label
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is used and reassigned w/o releasing the objects assigned to it.
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*/
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void Fl_Multi_Label::label(Fl_Widget* o) {
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o->label(FL_MULTI_LABEL, (const char*)this); // calls fl_define_FL_MULTI_LABEL()
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}
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/**
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Associate an Fl_Multi_Label with an Fl_Menu_Item.
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This uses Fl_Menu_Item::label(Fl_Labeltype a, const char *b) internally to
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set the \e label and the label type of the menu item, i.e. it stores a
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\e pointer to the Fl_Multi_Label object (\e this).
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An existing label (pointer) will be overwritten.
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This sets the type of the menu item's label to \_FL_MULTI_LABEL - note the
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leading underscore ('_').
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There is no way to use a method like Fl_Widget::copy_label() that transfers
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ownership of the Fl_Multi_Label and its linked objects (images, text, and
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chained Fl_Multi_Label's) to the menu item.
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The Fl_Multi_Label and all linked images, text labels, or chained
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Fl_Multi_Label objects must exist during the lifetime of the menu and
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will not be released when the menu item is destroyed.
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\note The user's code is responsible for releasing the Fl_Multi_Label and
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all linked objects (images, text, chained Fl_Multi_Label's) after the
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menu has been deleted. This may cause memory leaks if Fl_Multi_Label
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is used and reassigned w/o releasing the objects assigned to it.
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\deprecated since 1.4.0: please use Fl_Menu_Item::label(Fl_Multi_Label *)
|
||||
|
||||
\see Fl_Menu_Item::label(Fl_Multi_Label *)
|
||||
*/
|
||||
void Fl_Multi_Label::label(Fl_Menu_Item* o) {
|
||||
o->label(FL_MULTI_LABEL, (const char*)this); // calls fl_define_FL_MULTI_LABEL()
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user