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Agar 1.7 Manual

(Printable Version)


#include <agar/core.h>
#include <agar/gui.h>


ScreenshotAG_FileDlg is a traditional file selection widget. It displays a list of directories and shortcuts at the left, a list of files at the right and an input textbox and file type selector at the bottom. If supports filesystem monitoring via AG_AddEventSink(3). On platforms with glob(3) support, glob patterns may be entered in the input textbox.

Although AG_FileDlg is most often used to implement "Load" or "Save as..." dialog windows, it may also be embedded into any arbitrary container widget. User-specified actions (with optional parameters) can be tied to specific file extensions.

For selecting directories, the AG_DirDlg(3) widget may be used instead.


AG_Object(3)-> AG_Widget(3)-> AG_FileDlg.


AG_FileDlg * AG_FileDlgNew (AG_Widget *parent, Uint flags)

AG_FileDlg * AG_FileDlgNewMRU (AG_Widget *parent, const char *mruKey, Uint flags)

AG_FileDlg * AG_FileDlgNewCompact (AG_Widget *parent, const char *label, Uint flags)

AG_FileDlg * AG_FileDlgNewCompactMRU (AG_Widget *parent, const char *label, const char *mruKey, Uint flags)

char * AG_FileDlgGetDirectory (AG_FileDlg *fd)

AG_Size AG_FileDlgCopyDirectory (AG_FileDlg *fd, char *dst, AG_Size size)

int AG_FileDlgSetDirectory (AG_FileDlg *fd, const char *format, ...)

int AG_FileDlgSetDirectoryS (AG_FileDlg *fd, const char *path)

void AG_FileDlgSetDirectoryMRU (AG_FileDlg *fd, const char *mruKey, const char *defaultDir)

char * AG_FileDlgGetFilename (AG_FileDlg *fd)

AG_Size AG_FileDlgCopyFilename (AG_FileDlg *fd, char *dst, AG_Size size)

void AG_FileDlgSetFilename (AG_FileDlg *fd, const char *format, ...)

void AG_FileDlgSetFilenameS (AG_FileDlg *fd, const char *filename)

AG_FileType * AG_FileDlgAddType (AG_FileDlg *fd, const char *descr, const char *exts, void (*fn)(AG_Event *), const char *fnArgs, ...)

void AG_FileDlgAddImageTypes (AG_FileDlg *fd, void (*fn)(AG_Event *), const char *fnArgs, ...)

void AG_FileDlgCopyTypes (AG_FileDlg *dst, const AG_FileDlg *src)

void AG_FileDlgRefresh (AG_FileDlg *fd)

AG_FileDlgNew() allocates, initializes, and attaches a new AG_FileDlg.

The AG_FileDlgNewMRU() variant calls AG_FileDlgSetDirectoryMRU() with mruKey. Unless AG_FileDlgSetDirectory() is used (see below), the default directory is set according to the AG_CONFIG_PATH_DATA setting of AG_Config(3).

AG_FileDlgNewCompact() and AG_FileDlgNewCompactMRU() implicitely set the AG_FILEDLG_COMPACT flag as well as the contents of the display label.

Acceptable flags include:
AG_FILEDLG_COMPACTProxy mode. Collapse to a single-line textbox and "..." button. The expand button shows a regular AG_FileDlg in a new window. If the user selects a file and clicks "OK", the file path is copied to the textbox of the compact AG_FileDlg.
AG_FILEDLG_MASK_EXTMask unknown files by extension.
AG_FILEDLG_MASK_HIDDENMask hidden files.
AG_FILEDLG_MULTIAllow multiple files to be selected at once.
AG_FILEDLG_CLOSEWINAutomatically close the AG_FileDlg widget's parent window when a file is selected.
AG_FILEDLG_LOADThe selected file must exist and be readable or an error is returned to the user.
AG_FILEDLG_SAVEThe selected file must be writeable or an error is returned to the user.
AG_FILEDLG_ASYNCLoad/save routines will be executed in a separate thread. This flag is available only if agar was compiled with threads support.
AG_FILEDLG_NOMASKOPTSDon't display "Mask files by extension" and "Mask hidden files" checkboxes.
AG_FILEDLG_NOTYPESELECTDon't display the "Type:" selector dropbox.
AG_FILEDLG_NOBUTTONSDon't display "OK" and "Cancel" buttons.
AG_FILEDLG_HFILLExpand horizontally in parent container.
AG_FILEDLG_VFILLExpand vertically in parent container.

The working directory can be retrieved as a newly-allocated string using AG_FileDlgGetDirectory(), or copied into a fixed-size buffer with AG_FileDlgCopyDirectory(). AG_FileDlgSetDirectory().

AG_FileDlgSetDirectoryMRU() sets the working directory according to an AG_Config(3) parameter named mruKey. If the parameter does not exist, it will be set to defaultDir (it is customary to use a name such as myapp.mru.foofiles). If AG_FileDlgSetDirectoryMRU() is used, subsequent directory changes will cause the current AG_Config(3) settings to be saved automatically.

The current filename can be retrieved as a newly-allocated string using AG_FileDlgGetFilename(), or copied into a fixed-size buffer with AG_FileDlgCopyFilename().

The AG_FileDlgSetFilename() function sets the filename to initially display in the textbox. It is typically used in file saving dialogs.

AG_FileDlgAddType() registers a new type-specific event handler for a given file format (and associated set of filename extensions). If fn is non-NULL, it sets a type-specific callback to invoke when a file of the selected type is selected by the user. descr is a description of the file format and exts is a comma-separated list of filename extensions or special directives (enclosed in "<>"). Syntax for extensions include:
".txt" or "*.txt"Match all files ending in ".txt".
"<-x>"Match all files that are executable by the effective owner of the process (using AG_GetFileInfo(3)).
"<=hello.txt>"Only match hello.txt (case-sensitive exact match).
"<=hello.txt/i>"Match hello.txt, Hello.txt, etc (case-insensitive).

Type-specific handlers do not override the general "file-chosen" event handler when one exists (if both are set then the type-specific handler is run first, followed by "file-chosen").

AG_FileDlgAddImageTypes() registers a common handler for all image types recognized by AG_SurfaceFromFile(3) (such as BMP, PNG and JPEG).

AG_FileDlgCopyTypes() copies the set of AG_FileType (and any associated type-specific options), from one AG_FileDlg to another.

The AG_FileDlgRefresh() function updates the displayed directory structure and current directory contents.


By default, selecting a file will trigger the following checks:
  1. If AG_FILEDLG_LOAD or AG_FILEDLG_SAVE is set, check whether the file is readable or writeable.
  2. If AG_FILEDLG_SAVE is set and a file exists, display a "Replace file?" prompt.
  3. Execute the format-specific callback, as previously configured with AG_FileDlgAddType().
  4. If AG_FILEDLG_CLOSEWIN is set, close the parent window.

The default action performed when a user clicks on "Cancel" is simply to close the parent window if AG_FILEDLG_CLOSEWIN is set.

These default actions can be overridden using the functions below:

void AG_FileDlgOkAction (AG_FileDlg *fd, void (*fn)(AG_Event *), const char *fmt, ...)

void AG_FileDlgCancelAction (AG_FileDlg *fd, void (*fn)(AG_Event *), const char *fmt, ...)

int AG_FileDlgCheckReadAccess (AG_FileDlg *fd)

int AG_FileDlgCheckWriteAccess (AG_FileDlg *fd)

The AG_FileDlgOkAction() function configures an event handler function to invoke when a file is selected, overriding the default behavior. The event handler will be passed a string argument containing the absolute path to the selected file, followed by a pointer to the AG_FileType structure for the file type selected by the user (see STRUCTURE DATA for details).

AG_FileDlgCancelAction() overrides the default behavior of the "Cancel" button.

AG_FileDlgCheckReadAccess() and AG_FileDlgCheckWriteAccess() evaluate whether the selected file is readable or writeable.


When we are using AG_FileDlg to load and save files, we may want to provide the user with format-specific options that will affect the loading or saving process. Format-specific options are associated with a file type (an AG_FileType as returned by AG_FileDlgAddType()). When a file type is selected, AG_FileDlg displays basic widgets enabling the user to manipulate those options.

void AG_FileDlgSetOptionContainer (AG_FileDlg *fd, AG_Widget *container)

AG_FileOption * AG_FileOptionNewBool (AG_FileType *type, const char *descr, const char *key, int default)

AG_FileOption * AG_FileOptionNewInt (AG_FileType *type, const char *descr, const char *key, int default, int min, int max)

AG_FileOption * AG_FileOptionNewFlt (AG_FileType *type, const char *descr, const char *key, float default, float min, float max, const char *unit)

AG_FileOption * AG_FileOptionNewDbl (AG_FileType *type, const char *descr, const char *key, double default, double min, double max, const char *unit)

AG_FileOption * AG_FileOptionGet (AG_FileType *type, const char *key)

int AG_FileOptionBool (AG_FileType *type, const char *key)

int AG_FileOptionInt (AG_FileType *type, const char *key)

float AG_FileOptionFlt (AG_FileType *type, const char *key)

double AG_FileOptionDbl (AG_FileType *type, const char *key)

AG_FileDlgSetOptionContainer() arranges for the given container widget to hold the control widgets that will be dynamically created.

AG_FileOptionNewBool() registers a boolean option, manipulated by an AG_Checkbox(3). descr is a description string and key is a handle that the save/load routine will use to retrieve the option. default indicates the initial value of the option (1 = true, 0 = false).

AG_FileOptionNewInt() registers an integer option, manipulated by an AG_Numerical(3). default is the initial value, min and max define the bounds.

AG_FileOptionNewFlt() and AG_FileOptionNewDbl() register single and double precision floating-point options, using AG_Numerical(3). default is the initial value, min and max define the bounds and unit, if not NULL, is the unit system to use (see AG_Units(3)).

AG_FileOptionGet() returns a pointer to the AG_FileOption structure for the given option name, or NULL if there is no such option. AG_FileOptionBool(), AG_FileOptionInt(), AG_FileOptionFlt() and AG_FileOptionDbl() return the value of the given option.


The AG_FileDlg widget does not provide any bindings.


The AG_FileDlg widget generates the following events:
file-chosen (char *path, AG_FileType *type)
User has selected the given file. path is the full pathname to the file. If not NULL, type describes the matching type of the file.
file-selected (char *path)
User has moved selection over the given file, where path is the full pathname to it. This event is useful for things like previewing file contents using an external widget.
dir-selected (char *path)
The given directory was selected.


For the AG_FileDlg object:
char cwd[AG_PATHNAME_MAX] Absolute path of current working directory.
char cfile[AG_PATHNAME_MAX] Absolute path of last selected file.

For the AG_FileType structure (as returned by AG_FileDlgAddType()):
AG_FileDlg *fd Back pointer to the parent AG_FileDlg (read-only).
char **exts List of associated file extensions.
Uint nExts Count of file extensions.
const char *descr Description string (read-only).
AG_Event *action Callback function (as returned by AG_SetEvent(3)) to invoke when a file of this type is selected for a load/save operation.


See tests/loader.c in the Agar source distribution.



The AG_FileDlg widget first appeared in Agar 1.0. The AG_FILEDLG_COMPACT option as well as AG_FileDlgNewCompact(), AG_FileDlgNewCompactMRU(), AG_FileDlgGetDirectory(), AG_FileDlgCopyDirectory(), AG_FileDlgGetFilename(), AG_FileDlgCopyFilename(), AG_FileDlgCopyTypes() and AG_FileDlgAddImageTypes() routines appeared in Agar 1.6.0. ElectronTubeStore