Icon is a small graphics object that can be associated with various other user interface objects, such as buttons and tabs.

Creating Icons

To create an icon:

Create a sub folder 'icons', keeping all icons in a separate folder is a good programming practice

Paint your icon and save it as 8 bit Microsoft .ico image (say icons/foo.ico).

Create a makefile 'icons/makefile' for compiling your icons. The structure of the makefile is as follows:

   V4TARGET=mytoolset
   V4ICONWIDTH=24
   V4ICONHEIGHT=16
   V4ICONDEPTH=8

IFILES=foo.ico

!include $(V4HOME)/$(V4MKRES).mak

where V4TARGET must match the name of the library which will contain your icon.

Enter 'make' in the icons folder. This will create 'foo.h' file, which you can then include with your source file to actually use the icons graphics. On Windows, this will also create two resource files 'myplugin.rc' and 'myplugin.res'.

A button with an Icon

Most gadgets accep R3GA_Icon attribute, which you can use to pass an icon to the gadget. The following code creates a button with an icon.

#include <oops/r3icon.h>    /* icon class */
#include <oops/r3button.h>  /* button class */
#include "icons/foo.h"            /* my icon specific header */

/* create an icon object */
icon = R3New(R3CLID_ICON,
             R3ICONA_Data, foo_bits,
             R3ICONA_Width, foo_width,
             R3ICONA_Height, foo_height,
             R3ICONA_Depth, foo_depth,
	     R3TAG_END);


/* create a button which uses the icon */
button = R3New(R3CLID_BUTTON,
               R3GA_Icon, icon,
	       ...

Creating Icons with different Size

Because the icon size must be defined in the makefile, one has to create multiple makefiles in order to create icon sets with different size.

If you are implementing a plugin which implements both tools and geometric objects, you'll need to paint icons with two size:

Correspondingly, you will need to write two makefiles: one for 32x16 icons and one for the 24x16 icons:

V4LIBNAME=myplugin
V4TARGET=myplugin24
V4ICONWIDTH=24
V4ICONHEIGHT=16
V4ICONDEPTH=8
V4NORES=TRUE

IFILES=small.ico

!include $(V4HOME)/$(V4MKRES).mak

The V4NORES makefile tells the resource compiler that it should not compile the final binary, just generate the header files from the icons (and additional myplugin16.rc on windows).

The second makefile would look as follows:

V4LIBNAME=myplugin
V4TARGET=myplugin32
V4ICONWIDTH=32
V4ICONHEIGHT=16
V4ICONDEPTH=8
V4NORES=TRUE

IFILES=big.ico

!include $(V4HOME)/$(V4MKRES).mak

And then you need one additional makefile, say 'makejoin', which is needed to join the two intermediate resource files into the final myplugin.res. Note that this makejoin makefile is effective only on Windows platform. It doesn't do anything on other platforms.

V4TARGET=myplugin
RCFILES=myplugin24.rc myplugin32.rc

!include $(V4HOME)/$(V4MKRES).mak  

Typing three 'make' commands every time you need to rebuild the icons doesn't make any sense, so you should write fourth makefile, which takes care of everything in one 'make' command.

!include $(V4HOME)/$(V4OS).mak

all depend clean strings static:
	$(MAKE) $(MAKEOPTS) $@ -f make24x16
	$(MAKE) $(MAKEOPTS) $@ -f make32x16
	$(MAKE) $(MAKEOPTS) $@ -f makejoin

Another problem with .ico is that not that many image programs can write or read it (Microsoft Visual Studio is perhaps the most well know one). In fact, it is quite difficult to find an image format which would be more screwed up than Microsoft .ico.