1d73c0195c
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 *).
104 lines
4.2 KiB
C++
104 lines
4.2 KiB
C++
//
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// Multi-label header file for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2023 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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// file is missing or damaged, see the license at:
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//
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// https://www.fltk.org/COPYING.php
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//
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// Please see the following page on how to report bugs and issues:
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//
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// https://www.fltk.org/bugs.php
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//
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#ifndef Fl_Multi_Label_H
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#define Fl_Multi_Label_H
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class Fl_Widget;
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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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\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, \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 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 \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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\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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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 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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// 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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// 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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// 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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// 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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a (Fl_Image*) or a (Fl_Multi_Label*). */
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const char* labela;
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/** Holds the "rightmost" 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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a (Fl_Image*) or a (Fl_Multi_Label*). */
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const char* labelb;
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/** Holds the "type" of labela.
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Typically this is set to FL_NORMAL_LABEL for a text label,
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FL_IMAGE_LABEL for an image (based on Fl_image) or FL_MULTI_LABEL
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if "chaining" multiple Fl_Multi_Label elements together. */
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uchar typea;
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/** Holds the "type" of labelb.
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Typically this is set to FL_NORMAL_LABEL for a text label,
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FL_IMAGE_LABEL for an image (based on Fl_image) or 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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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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void label(Fl_Menu_Item*);
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};
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#endif
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