153 lines
6.8 KiB
Plaintext
153 lines
6.8 KiB
Plaintext
SDL Considerations
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==================
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There are no special requirements to use PDCurses for SDL -- all
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PDCurses-compatible code should work fine. (In fact, you can even build
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against the Win32 console pdcurses.dll, and then swap in the SDL
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pdcurses.dll.) Nothing extra is needed beyond the base SDL library.
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However, there are some optional special features, described here.
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The principal limitation of this port is that input is currently
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restricted to ASCII (i.e., 0-127), plus the special keys like KEY_LEFT.
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(You could have Unicode input, but then the input wouldn't match the
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output, which is in Code Page 437.) Also, see the note about the
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potential for incomplete output under "PDC_update_rects()", below.
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Fonts
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-----
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The font is a simple BMP, 32 characters wide by 8 characters tall,
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preferably with a palette. (BMPs without palettes still work, but in
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that case, no attributes will be available, nor will the cursor work.)
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The first entry in the palette (usually black) is treated as the
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background color; the last entry (usually white) is treated as the
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foreground. These are changed or made transparent as appropriate; any
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other colors in the palette are passed through unchanged. So -- although
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a one-bit depth is sufficient for a normal font -- you could redraw some
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characters as multi-colored tiles.
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The font must be monospaced. The size of each character is derived by
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dividing the width of the BMP by 32 and the height by 8. There is no
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constraint on the dimensions.
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As provided in the default font and expected by acs_map[], the font is
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in Code Page 437 form. But you can of course use any layout if you're
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not relying on correct values for the ACS_* macros.
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The font can be set via the environment variable PDC_FONT. If it's not
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set, PDCurses looks for a file named "pdcfont.bmp" in the current
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directory at the time of initscr(). If neither is found, it uses the
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built-in default font encoded in deffont.h.
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Backgrounds
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-----------
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PDCurses for SDL supports an optional background image BMP. This is used
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whenever start_color() has not been called (see the ptest demo for an
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example), or when use_default_colors() has been called after
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start_color(), and the background color of a pair has been set to -1
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(see newdemo, worm, and rain for examples). The usage parallels that of
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ncurses in an appropriate terminal (e.g., Gnome Terminal). The image is
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tiled to cover the PDCurses window, and can be any size or depth.
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As with the font, you can point to a location for the background via the
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environment variable PDC_BACKGROUND; "pdcback.bmp" is the fallback.
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(There is no default background.)
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Icons
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-----
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The icon (used with SDL_WM_SetIcon() -- not used for the executable
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file) can be set via the environment variable PDC_ICON, and falls back
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to "pdcicon.bmp", and then to the built-in icon from deficon.h. The
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built-in icon is the PDCurses logo, as seen in ../x11/little_icon.xbm.
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The SDL docs say that the icon must be 32x32, at least for use with MS
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Windows.
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If pdc_screen is preinitialized (see below), PDCurses does not attempt
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to set the icon.
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Screen size
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-----------
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The default screen size is 80x25 characters (whatever size they may be),
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but you can override this via the environment variables PDC_COLS and/or
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PDC_LINES. (Some other ports use COLS and LINES; this is not done here
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because those values are, or should be, those of the controlling
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terminal, and PDCurses for SDL is independent of the terminal.) If
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pdc_screen is preinitialized (see below), these are ignored.
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Integration with SDL
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--------------------
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If you want to go further, you can mix PDCurses and SDL functions. (Of
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course this is extremely non-portable!) To aid you, there are several
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external variables and functions specific to the SDL port; you could
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include pdcsdl.h, or just add the declarations you need in your code:
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PDCEX SDL_Surface *pdc_screen, *pdc_font, *pdc_icon, *pdc_back;
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PDCEX int pdc_sheight, pdc_swidth, pdc_yoffset, pdc_xoffset;
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void PDC_update_rects(void);
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void PDC_retile(void);
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pdc_screen is the main surface, created by SDL_SetVideoMode(), unless
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it's preset before initscr(). You can perform normal SDL operations on
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this surface, but PDCurses won't respect them when it updates. (For
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that, see PDC_retile().) As an alternative, you can preinitialize this
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surface before calling initscr(). In that case, you can use pdc_sheight,
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pdc_swidth, pdc_yoffset and/or pdc_xoffset (q.v.) to confine PDCurses to
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only a specific area of the surface, reserving the rest for other SDL
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operations. If you preinitialize pdc_screen, you'll have to close it
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yourself; PDCurses will ignore resize events, and won't try to set the
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icon. Also note that if you preinitialize pdc_screen, it need not be the
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display surface.
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pdc_font, pdc_icon, and pdc_back are the SDL_surfaces for the font,
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icon, and background, respectively. You can set any or all of them
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before initscr(), and thus override any of the other ways to set them.
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But note that pdc_icon will be ignored if pdc_screen is preset.
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pdc_sheight and pdc_swidth are the dimensions of the area of pdc_screen
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to be used by PDCurses. You can preset them before initscr(); if either
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is not set, it defaults to the full screen size minus the x or y offset,
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as appropriate.
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pdc_xoffset and pdc_yoffset are the x and y offset for the area of
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pdc_screen to be used by PDCurses. See the sdltest demo for an example.
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PDC_retile() makes a copy of pdc_screen, then tiles it with the
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background image, if any. The resulting surface is used as the
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background for transparent character cells. PDC_retile() is called from
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initscr() and resize_term(). However, you can also use it at other
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times, to take advantage of the way it copies pdc_screen: Draw some SDL
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stuff; call PDC_retile(); do some curses stuff -- it will use whatever
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was on pdc_screen as the background. Then you can erase the curses
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screen, do some more SDL stuff, and call PDC_retile() again to make a
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new background. (If you don't erase the curses screen, it will be
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incorporated into the background when you call PDC_retile().) But this
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only works if no background image is set.
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PDC_update_rects() is how the screen actually gets updated. For
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performance reasons, when drawing, PDCurses for SDL maintains a table of
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rectangles that need updating, and only updates (by calling this
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function) during getch(), napms(), or when the table gets full.
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Normally, this is sufficient; but if you're pausing in some way other
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than by using napms(), and you're not doing keyboard checks, you may get
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an incomplete update. If that happens, you can call PDC_update_rects()
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manually.
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Interaction with stdio
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----------------------
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As with X11, it's a bad idea to mix curses and stdio calls. (In fact,
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that's true for PDCurses on any platform; but especially these two,
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which don't run under terminals.) Depending on how SDL is built, stdout
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and stderr may be redirected to files.
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