optional support for PNG screenshots

You need to have SDL2_Image installed and run ./configure --with-sdlimage

Source/Makefile.am

@@ -78,5 +78,5 @@ winmbf_SOURCES = \
 	w_wad.c    w_wad.h \
 	wi_stuff.c wi_stuff.h \
 	z_zone.c   z_zone.h
-winmbf_CFLAGS = @SDL_CFLAGS@ @SDL_mixer_CFLAGS@ @SDL_net_CFLAGS@
-winmbf_LDADD = @SDL_LIBS@ @SDL_mixer_LIBS@ @SDL_net_LIBS@
+winmbf_CFLAGS = @SDL_CFLAGS@ @SDL_image_CFLAGS@ @SDL_mixer_CFLAGS@ @SDL_net_CFLAGS@
+winmbf_LDADD = @SDL_LIBS@ @SDL_image_LIBS@ @SDL_mixer_LIBS@ @SDL_net_LIBS@

Source/i_video.c

@@ -31,6 +31,11 @@ rcsid[] = "$Id: i_video.c,v 1.12 1998/05/03 22:40:35 killough Exp $";
 
 #include "SDL.h" // haleyjd
 
+#include "config.h"
+#ifdef HAVE_SDL_IMAGE
+#include "SDL_image.h"
+#endif
+
 #include "z_zone.h"  /* memory allocation wrappers -- killough */
 #include "doomstat.h"
 #include "v_video.h"
@@ -685,6 +690,13 @@ void I_ShutdownGraphics(void)
    }
 }
 
+boolean I_WritePNGfile(char *filename)
+{
+#ifdef HAVE_SDL_IMAGE
+   return IMG_SavePNG(sdlscreen, filename) == 0;
+#endif
+}
+
 extern boolean setsizeneeded;
 
 extern void I_InitKeyboard();

Source/i_video.h

@@ -60,6 +60,8 @@ extern int page_flip;  // killough 8/15/98: enables page flipping (320x200)
 extern int disk_icon;  // killough 10/98
 extern int hires;      // killough 11/98
 
+boolean I_WritePNGfile(char *filename);
+
 #endif
 
 //----------------------------------------------------------------------------

Source/m_menu.c

@@ -3065,7 +3065,11 @@ setup_menu_t gen_settings1[] = { // General Settings screen1
   {"Translucency filter percentage", S_NUM, m_null, G_X,
    G_Y + general_transpct*8, {"tran_filter_pct"}, 0, 0, M_Trans},
 
+#ifdef HAVE_SDL_IMAGE
+  {"PCX instead of PNG for screenshots", S_YESNO, m_null, G_X,
+#else
   {"PCX instead of BMP for screenshots", S_YESNO, m_null, G_X,
+#endif
    G_Y + general_pcx*8, {"screenshot_pcx"}},
 
   {"Flash Icon During Disk IO", S_YESNO, m_null, G_X,

Source/m_misc.c

@@ -1031,7 +1031,11 @@ default_t defaults[] = {
     "screenshot_pcx",
     &screenshot_pcx, NULL,
     1, {0,1}, number, ss_gen, wad_no,
+#ifdef HAVE_SDL_IMAGE
+    "1 to take a screenshot in PCX format, 0 for PNG"
+#else
     "1 to take a screenshot in PCX format, 0 for BMP"
+#endif
   },
 
   {
@@ -2359,6 +2363,12 @@ boolean WriteBMPfile(char *filename, byte *data, int width,
   return I_EndRead(), true;       // killough 10/98
 }
 
+boolean WritePNGfile(char *filename, byte *data, int width,
+                     int height, byte *palette)
+{
+  return I_WritePNGfile(filename);
+}
+
 //
 // M_ScreenShot
 //
@@ -2381,7 +2391,11 @@ void M_ScreenShot (void)
 
       do
         sprintf(lbmname,                         //jff 3/30/98 pcx or bmp?
+#ifdef HAVE_SDL_IMAGE
+                screenshot_pcx ? "doom%02d.pcx" : "doom%02d.png", shot++);
+#else
                 screenshot_pcx ? "doom%02d.pcx" : "doom%02d.bmp", shot++);
+#endif
       while (!access(lbmname,0) && --tries);
 
       if (tries)
@@ -2399,7 +2413,11 @@ void M_ScreenShot (void)
 
           // killough 10/98: detect failure and remove file if error
 	  // killough 11/98: add hires support
+#ifdef HAVE_SDL_IMAGE
+          if (!(success = (screenshot_pcx ? WritePCXfile : WritePNGfile)
+#else
           if (!(success = (screenshot_pcx ? WritePCXfile : WriteBMPfile)
+#endif
                 (lbmname,linear, SCREENWIDTH<<hires, SCREENHEIGHT<<hires,pal)))
 	    {
 	      int t = errno;

configure.ac

@@ -17,6 +17,13 @@ PKG_CHECK_MODULES([SDL_mixer], [SDL2_mixer])
 PKG_CHECK_MODULES([SDL_net],   [SDL2_net])
 AC_DEFINE([MY_SDL_VER], [1], [This is WinMBF])
 
+AC_ARG_WITH([sdlimage], AS_HELP_STRING([--with-sdlimage], [Build with SDL2_Image for PNG screenshots]))
+AS_IF([test "x$with_sdlimage" = "xyes"],
+	[PKG_CHECK_MODULES([SDL_image], [SDL2_image],
+		[AC_DEFINE([HAVE_SDL_IMAGE], [1], [PNG screenshots])]
+	)]
+)
+
 # Checks for header files.
 AC_CHECK_HEADERS([fcntl.h limits.h malloc.h stddef.h stdint.h stdlib.h string.h unistd.h])