use libpng, ... now we just have to make it faster

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

8 files changed, 197 insertions, 29 deletions

diff --git a/DEPENDENCIES b/DEPENDENCIES
index d97fafc..c1b1eb0 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -11,6 +11,7 @@ BUILD DEPENDENCIES:
 	coreutils
 	glibc (any libc with getopt_long)
 	libpng
+	pkg-config
 	c99
 	gettext (opt-out, for internationalisation)
 	texinfo (opt-out, for info, pdf, dvi, ps, and html manuals)
diff --git a/Makefile.in b/Makefile.in
index 939647d..4f812f4 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -56,9 +56,12 @@ _VERSION = 2.0
 _C_STD = c99
 _PEDANTIC = yes
 _BIN = scrotty
-_OBJ_scrotty = scrotty kern-linux info pattern
+_OBJ_scrotty = scrotty kern-linux info pattern png
 _HEADER_DIRLEVELS = 1
 _CPPFLAGS = -D'PACKAGE="$(PKGNAME)"' -D'PROGRAM_VERSION="$(_VERSION)"'
+_CPPFLAGS += $(shell pkg-config --cflags libpng)
+#  -I is a CPPFLAG, not a CFLAG
+_LDFLAGS += $(shell pkg-config --libs libpng)
 
 # Used by mk/i18n.mk
 _SRC = $(foreach B,$(_BIN),$(foreach F,$(_OBJ_$(B)),$(F).c))
@@ -85,7 +88,7 @@ ___EVERYTHING_INFO = scrotty titlepage-data content hardcopy-copying  \
                    appx/fdl appx/free-software-needs-free-documentation appx/gpl  \
                    chap/invoking chap/overview chap/strftime  \
                    reusable/macros reusable/paper reusable/titlepage
-___EVERYTHING_H = common kern info pattern pnm
+___EVERYTHING_H = common kern info pattern pnm png
 _EVERYTHING = $(foreach F,$(___EVERYTHING_INFO),doc/info/$(F).texinfo)  \
               $(foreach F,$(___EVERYTHING_H),src/$(F).h)  \
               $(__EVERYTHING_ALL_COMMON) DEPENDENCIES INSTALL NEWS $(__todo) doc/concept
diff --git a/doc/info/chap/invoking.texinfo b/doc/info/chap/invoking.texinfo
index d418fc2..bb4d8db 100644
--- a/doc/info/chap/invoking.texinfo
+++ b/doc/info/chap/invoking.texinfo
@@ -26,9 +26,15 @@ bytes in difference.} and can in fact be smaller.
 
 @sc{PNM} is a good alternative for anything
 but storage. (Unless you compress them.)
+
+This option is also useful, in combination with
+@option{--exec} if you want to save the image
+in any other format.
 @item -e
 @itemx --exec CMD
 Run a command for each saved image.
+
+Can only be specified once.
 @end table
 
 In addition to these options, a filename
@@ -36,10 +42,6 @@ pattern, that does not start with a dash,
 can be added. This filename pattern selects
 with what filename the image should be saved.
 
-Further, it is possible add @option{--}
-followed by additional options to add when
-@command{scrotty} spawns @command{convert}.
-
 Both the @option{--exec} and filename pattern
 parameters can take format specifiers that are
 expanded by @command{scrotty} when encountered.
diff --git a/mk/lang-c.mk b/mk/lang-c.mk
index 5d952b6..b8076d6 100644
--- a/mk/lang-c.mk
+++ b/mk/lang-c.mk
@@ -112,11 +112,11 @@ _CPPFLAGS += $(foreach D,$(_ALL_DIRS),-D'$(D)="$($(D))"')
 # MORE HELP VARIABLES:
 
 # Compilation and linking flags, and command.
-CPPFLAGS = $(_CPPFLAGS)
-CFLAGS = $(OPTIMISE) $(WARN) $(_CFLAGS)
-LDFLAGS = $(OPTIMISE) $(WARN) $(_LDFLAGS)
-__CC = $(CC) -std=$(_C_STD) -c
-__LD = $(CC) -std=$(_C_STD) 
+CPPFLAGS =
+CFLAGS = $(OPTIMISE) $(WARN)
+LDFLAGS = $(OPTIMISE) $(WARN)
+__CC = $(CC) -std=$(_C_STD) -c $(_CPPFLAGS) $(_CFLAGS)
+__LD = $(CC) -std=$(_C_STD) $(_LDFLAGS)
 __CC_POST = $(CPPFLAGS) $(CFLAGS) $(EXTRA_CPPFLAGS) $(EXTRA_CFLAGS)
 __LD_POST = $(LDFLAGS) $(EXTRA_LDFLAGS)
 
diff --git a/po/sv.po b/po/sv.po
index a048ef0..5671231 100644
--- a/po/sv.po
+++ b/po/sv.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: scrotty 1.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2015-12-10 22:45+0100\n"
+"POT-Creation-Date: 2015-12-11 11:19+0100\n"
 "PO-Revision-Date: 2015-12-07 18:50+0100\n"
 "Last-Translator: Mattias Andrée <maandree@member.fsf.org>\n"
 "Language-Team: none\n"
@@ -17,34 +17,34 @@ msgstr ""
 "Content-Transfer-Encoding: 8bit\n"
 "Plural-Forms: nplurals=2; plural=(n != 1);\n"
 
-#: src/scrotty.c:373
+#: src/scrotty.c:376
 #, c-format
 msgid "Saved framebuffer %i to %s.\n"
 msgstr "Bildrutebuffert %i sparad till %s.\n"
 
-#: src/scrotty.c:468 src/scrotty.c:472 src/scrotty.c:478
+#: src/scrotty.c:471 src/scrotty.c:475 src/scrotty.c:481
 #, c-format
 msgid "%s: %s. Type '%s --help' for help.\n"
 msgstr "%s: %s. Kör '%s --help' för hjälp.\n"
 
-#: src/scrotty.c:468
+#: src/scrotty.c:471
 msgid "--exec is used twice."
 msgstr "--exec förkommer mer än en gång."
 
-#: src/scrotty.c:472
+#: src/scrotty.c:475
 msgid "Invalid input."
 msgstr "Ogiltig indata."
 
-#: src/scrotty.c:478
+#: src/scrotty.c:481
 msgid "FILENAME-PATTERN is used twice."
 msgstr "FILNAMNSMÖNSTER förekommer mer än en gång"
 
-#: src/scrotty.c:509
+#: src/scrotty.c:512
 #, c-format
 msgid "%s: It looks like you are inside a display server. If this is correct, what you see is probably not what you get.\n"
 msgstr "%s: Det ser ut som att du är innan för en grafikserver. Om detta är korrect, vad de ser är troligtvis inte vad du får.\n"
 
-#: src/scrotty.c:519
+#: src/scrotty.c:522
 #, c-format
 msgid "%s: %s: %s\n"
 msgstr "%s: %s: %s\n"
diff --git a/src/png.c b/src/png.c
new file mode 100644
index 0000000..0944f18
--- /dev/null
+++ b/src/png.c
@@ -0,0 +1,130 @@
+/**
+ * scrotty — Screenshot program for Linux's TTY
+ * 
+ * Copyright © 2014, 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "common.h"
+#include "png.h"
+
+#ifdef __GNUC__
+# pragma GCC diagnostic ignored "-Wpadded"
+#endif
+#include <png.h>
+
+
+/*
+ * Rationale:
+ * 
+ *   Users want their files in PNG (most often), not PNM.
+ *   Calling an external program for conversion poses
+ *   potential security risks, and is slower.
+ */
+
+
+/**
+ * Convert an image from PNM to PNG.
+ * 
+ * This is a very limited conversion implementation.
+ * It is not generally reusable. It makes assumptions
+ * that are true only necessarily for this program.
+ * 
+ * @param   fdin   The file descriptor for the image to convert (PNM).
+ * @param   fdout  The file descriptor for the output image (PNG).
+ * @return         Zero on success, -1 on error.
+ */
+int
+convert (int fdin, int fdout)
+{
+#define SCAN(...)  do { if (fscanf(in, __VA_ARGS__) != 1)  goto fail; } while (0)
+
+  FILE *in = NULL;
+  FILE *out = NULL;
+  long height, width, width3;
+  long y, x, r, g, b;
+  png_byte   *pixbuf = 0;
+  png_struct *pngbuf = NULL;
+  png_info   *pnginfo = NULL;
+  int saved_errno = 0, rc, c;
+  
+  /* Get a FILE * for the input, we want to use fscanf, there is no dscanf. */
+  in = fdopen (fdin, "r");
+  if (in == NULL)
+    goto fail;
+  /* Get a FILE * for the output, libpng wants a FILE *, not a file descriptor. */
+  out = fdopen (fdout, "w");
+  if (out == NULL)
+    goto fail;
+  
+  /* Read head. */
+  do c = fgetc(in); while ((c != '\n') && (c != EOF));
+  SCAN ("%li ", &width);
+  SCAN ("%li\n", &height);
+  do c = fgetc(in); while ((c != '\n') && (c != EOF));
+  
+  /* Allocte structures for the PNG. */
+  width3 = width * 3;
+  pixbuf = malloc ((size_t)width3 * sizeof (png_byte));
+  if (pixbuf == NULL)
+    goto fail;
+  pngbuf = png_create_write_struct (png_get_libpng_ver (NULL), NULL, NULL, NULL);
+  if (pngbuf == NULL)
+    goto fail;
+  pnginfo = png_create_info_struct (pngbuf);
+  if (pnginfo == NULL)
+    goto fail;
+  
+  /* Initialise PNG write, and write head. */
+  if (setjmp (png_jmpbuf(pngbuf))) /* Failing libpng calls jump here. */
+    goto fail;
+  png_init_io (pngbuf, out);
+  png_set_IHDR (pngbuf, pnginfo, (png_uint_32)width, (png_uint_32)height,
+		8 /* bit depth */, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+		PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+  png_write_info (pngbuf, pnginfo);
+  
+  /* Read and convert body. */
+  for (y = 0; y < height; y++)
+    {
+      for (x = 0; x < width3; x += 3)
+	{
+	  SCAN ("%li\n", &r);
+	  SCAN ("%li\n", &g);
+	  SCAN ("%li\n", &b);
+	  pixbuf[x + 0] = (png_byte)r;
+	  pixbuf[x + 1] = (png_byte)g;
+	  pixbuf[x + 2] = (png_byte)b;
+	}
+      png_write_row (pngbuf, pixbuf);
+    }
+  png_write_end (pngbuf, pnginfo);
+  
+  rc = 0;
+  goto cleanup;
+ fail:
+  saved_errno = errno;
+  rc = -1;
+  goto cleanup;
+  
+ cleanup: 
+  png_destroy_write_struct (&pngbuf, (pnginfo ? &pnginfo : NULL));
+  if (in != NULL)
+    fclose (in);
+  if (out != NULL)
+    fclose (out);
+  free (pixbuf);
+  return errno = saved_errno, rc;
+}
+
diff --git a/src/png.h b/src/png.h
new file mode 100644
index 0000000..02a6223
--- /dev/null
+++ b/src/png.h
@@ -0,0 +1,29 @@
+/**
+ * scrotty — Screenshot program for Linux's TTY
+ * 
+ * Copyright © 2014, 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/**
+ * Convert an image from PNM to PNG.
+ * 
+ * @param   fdin   The file descriptor for the image to convert (PNM).
+ * @param   fdout  The file descriptor for the output image (PNG).
+ * @return         Zero on success, -1 on error.
+ */
+int convert (int fdin, int fdout);
+
diff --git a/src/scrotty.c b/src/scrotty.c
index da69cc9..9837a26 100644
--- a/src/scrotty.c
+++ b/src/scrotty.c
@@ -21,6 +21,7 @@
 #include "kern.h"
 #include "info.h"
 #include "pnm.h"
+#include "png.h"
 #include "pattern.h"
 
 #include <getopt.h>
@@ -188,6 +189,7 @@ save (const char *fbpath, const char *imgpath, long width, long height, int raw)
   if (raw)
     goto no_convert;
   
+  
   /* Create a pipe that for sending data into the conversion process program. */
   if (pipe (pipe_rw) < 0)
     goto fail;
@@ -203,17 +205,18 @@ save (const char *fbpath, const char *imgpath, long width, long height, int raw)
     {
       /* Close the write-end of the pipe. */
       close (pipe_rw[1]);
-      /* Turn the read-end of the pipe into stdin. */
-      if (pipe_rw[0] != STDIN_FILENO)
-	{
-	  close (STDIN_FILENO);
-	  if (dup2 (pipe_rw[0], STDIN_FILENO) == -1)
-	    goto child_fail;
-	  close (pipe_rw[0]);
-	}
-      /* Exec. `convert` to convert the PNM-image we create to a compressed image. */
-      execlp ("convert", "convert", DEVDIR "/stdin", imgpath, NULL);
       
+      /* Open file descriptor for the output image. */
+      fd = open(imgpath, O_WRONLY | O_CREAT | O_TRUNC,
+		S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+      if (fd == -1)
+	goto child_fail;
+      
+      /* Convert the PNM-image we create to a compressed image, namely in PNG. */
+      if (convert (pipe_rw[0], fd) < 0)
+	goto child_fail;
+      
+      _exit(0);
     child_fail:
       perror(execname);
       _exit(1);