Some time ago, Ben Wing wrote...
|+
| I think you should implement this using the standard property mechanism for Lisp
| objects.
|
| There are a million strange properties for a device under X, such as "does
| backing store" (Aren't there some other weird hacks that exist for this?).
| Unfortunately, most of the properties that you implemented for Windows exist
| under X only in the context of an add-on package such as Motif or CDE. Anyone
| want to implement a CDE interface for XEmacs?
I have been thinking about using properties for that, and my opinion is that
a separate function would do better. These properties are different that
"regular" object properties in so that
- they are never settable;
- we cannot allow a window system not to have one of these. They are
numerous, and if someone sets any of these under a window system
which treats this property as "just a symbol", this code will fail
under another window system which treats a property by the same name
specially. This will likely be a source of bugs.
- Getting "device-properties" may be costly. We cannot disallow getting
a list of all properties. For "metrics" which are different than
properties this is ok though when they are not availble wholesale.
The properties I listed are not specific for Windows, I think there
are only 75% of these are obtainable from Windows. I tried to compile
a list of properties useful as XEmacs fallbacks for different geometrical
metrics, so "does backing store" perhaps not worthy listing here.
Kirill
|
| Kirill M. Katsnelson wrote:
|
| > I implemented a single lisp function, which returns many information
| > aspects about the window system. There were six such functions already:
| > device-{pixel,mm}-{height,width}, device-bitplanes, device-color-cells.
| > Recently I added a Windows specific function which obtain default
| > scrollbar sizes. If this continues, there will be a flood of device
| > specific functions.
| >
| > You pass this function a device and a symbol for the capability you
| > want, and it returns metric's value. May I please ask everyone to
| > review the current list of capabilities, and to add what I missed?
| > Maybe not restricted to X and MS Windows, anything which fits into a
| > window system model and applies to XEmacs.
| >
| > Another question is which of these metrics are supported by X.
| > I implmented only 6 old metrics, maybe an X server can be asked
| > for more information?
| >
| > Here's a docstring, to avoid snarfing the patch file:
| >
| > DEFUN ("device-system-metrics", Fdevice_system_metrics, 2, 2, 0, /*
| > Get metrics for DEVICE as provided by the system.
| >
| > METRIC must be a symbol specifying requested metric. Note that
| > the metrics returned are these provided by the system internally,
| > not read from resources, so obtained from the mostly internal level.
| >
| > If a metric is not provided by the system, return value is nil.
| > Boolean values are returned as zero and non-zero integers.
| >
| > Metrics, by group, are:
| >
| > COLORS. Colors are returned as valid color instantiators. No other
| > assumption on the returned valie should be made (i.e. it can be a
| > string on one system but a color instance on another). For colors,
| > returned value is a cons of foreground and background colors. Note
| > that if the system provides only one color of the pair, the second
| > one may be nil.
| >
| > 'color-default Standard window text foreground and background.
| > 'color-select Selection highligh text and backgroun colors.
| > 'color-balloon Ballon popup text and background colors.
| > 'color-3d-face 3-D object (button, modeline) text and surface colors.
| > 'color-3d-light Fore and back colors for 3-D edges facing light source.
| > 'color-3d-dark Fore and back colors for 3-D edges facing away from
| > light source.
| > 'color-menu Text and background for menus
| > 'color-menu-high Selected menu item colors
| > 'color-menu-button Menu button colors
| > 'color-menu-unsel Unselectable menu item colors
| > 'color-toolbar Toolbar foreground and background colors
| > 'color-scrollbar Scrollbar foreground and background colors
| > 'color-desktop Desktop window colors
| > 'color-workspace Workspace window colors
| >
| > FONTS. Fonts are returned as valid font instantiators. No other
| > assumption on the returned value should be made (i.e. it can be a
| > string on one system but font instance on another).
| >
| > 'font-default Default fixed width font.
| > 'font-menubar Menubar font
| > 'font-dialog Dialog boxes font
| >
| > GEOMETRY. These metrics are returned as conses of (X . Y). As with colors,
| > either car or cdr of the cons may be nil if the system does not provide one
| > of corresponding dimensions.
| > 'size-cursor Mouse cursor size.
| > 'size-scrollbar Scrollbars (WIDTH . HEIGHT)
| > 'size-menu Menubar height, as (nil . HEIGHT)
| > 'size-toolbar Toolbar width and height.
| > 'size-tbbutton Toolbar button size.
| > 'size-tbborder Toolbar border width and height.
| > 'size-icon Icon dimensions.
| > 'size-icon-small Small icon dimensions.
| > 'size-device Device screen size in pixels.
| > 'size-workspace Workspace size in pixels. This can be less than the above
| > if window manager has decorations which effectively shrink
| > the area remaining for application windows.
| > 'size-device-mm Device screen size in millimeters.
| > 'device-dpi Device resolution, in dots per inch.
| >
| > 'num-bit-planes Integer, number of deive bit planes.
| > 'num-color-cells Integer, number of device color cells.
| >
| > FEATURES. This group reports various device features. Boolean values retuned
| > as integer 1 for true and zero for false, or nil if the feature is unknown
| > for the system.
| >
| > 'mouse-buttons Number of mouse buttons, or zero if no mouse (integer).
| > 'swap-buttons Non-zero if left and right mouse buttons are swapped
| > 'show-sounds User preference for visual over audible bell (boolean).
| > 'slow-device Device is slow, avoid animation (boolean).
| > 'security Non-zero if user environment is secure.
| > 'dbcs Window system supports DBCS (boolean).
| > 'ime Device embeds an input method editor (boolean).
| > 'mid-east Non-zero if the window system is enabled for Hebrew
| > and Arabic (left-to-right reading) languages.
| > */
| > (device, metric))
| >
| > Steve, I haven't built with tty and X, only compiled for syntax check
| > (build with X still fails on NT, and I'm far away from solaris). Could
| > you please ensure that the 6 (2 on ttys) moved lisp functions return
| > correct values? I C-x C-e'ed them right in ChangeLog :) TIA.
| >
|-
