[Qemu-devel] [PATCH] PNG screendump output alternative

[Rafael]

Hi,

 I  had already started to work on supporting PNG dump output on
screendump when got to know there was another effort to do the same
 (see Add PNG screendump thread from Daniel P. Berrange). Anyway, I'd
 like to share my implementation which is a little bit different. It
 does not use any resource/lib besides libpng and qemu itself and is
 based on qemu-kvm 0.15.1 ppm_save code.

 I'm using that for a personal project developed at Mandriva which uses
 QMP directly to communicate with qemu VMs rather than using the
 libvirt although its usage is considered for the future. There is
 something more to show but it is just QMP related and soon I'll have
 it done to share.

 Comments and suggestions are appreciated.

 Cheers
 Rafael Cabral

--- configure   2011-10-19 13:54:48.000000000 +0000
+++ configure   2012-03-15 13:33:26.000000000 +0000
@@ -141,6 +141,7 @@
 attr=""
 vhost_net=""
 xfs=""
+dump_png=""

 gprof="no"
 debug_tcg="no"
@@ -790,6 +791,10 @@
   ;;
   --disable-guest-agent) guest_agent="no"
   ;;
+  --disable-dump-png) dump_png="no"
+  ;;
+  --enable-dump-png) dump_png="yes"
+  ;;
   *) echo "ERROR: unknown option $opt"; show_help="yes"
   ;;
   esac
@@ -1075,6 +1080,8 @@
 echo "  --enable-usb-redir       enable usb network redirection support"
 echo "  --disable-guest-agent    disable building of the QEMU Guest Agent"
 echo "  --enable-guest-agent     enable building of the QEMU Guest Agent"
+echo "  --disable-dump-png       disable PNG for screendump output"
+echo "  --enable-dump-png        enable PNG for screendump output"
 echo ""
 echo "NOTE: The object files are built at the place where configure
is launched"
 exit 1
@@ -2610,6 +2617,40 @@
 fi

 ##########################################
+# DUMP PNG detection
+if test "$dump_png" = "yes" ; then
+cat > $TMPC <<EOF
+//#include <stdio.h>
+#include <png.h>
+#include <stddef.h>
+int main(void) {
+    png_structp png_ptr;
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    return 0;
+}
+EOF
+  if $pkg_config libpng --modversion >/dev/null 2>&1; then
+    dump_png_cflags=`$pkg_config libpng --cflags 2> /dev/null`
+    dump_png_libs=`$pkg_config libpng --libs 2> /dev/null`
+  else
+    dump_png_cflags=""
+    dump_png_libs="-lpng"
+  fi
+  if compile_prog "$dump_png_cflags" "$dump_png_libs" ; then
+    dump_png=yes
+    libs_softmmu="$dump_png_libs $libs_softmmu"
+  else
+    if test "dump_png" = "yes" ; then
+      feature_not_found "dump-png"
+    fi
+    dump_png=no
+  fi
+fi
+#########################################
+
+
+
+##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs

@@ -2776,6 +2817,7 @@
 echo "usb net redir     $usb_redir"
 echo "OpenGL support    $opengl"
 echo "build guest agent $guest_agent"
+echo "Dump png $dump_png"

 if test $sdl_too_old = "yes"; then
 echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -3083,6 +3125,11 @@
   echo "CONFIG_OPENGL=y" >> $config_host_mak
 fi

+if test "$dump_png" = "yes" ; then
+  echo "CONFIG_DUMP_PNG=y" >> $config_host_mak
+  echo "DUMP_PNG_CFLAGS=$dump_png_cflags" >> $config_host_mak
+fi
+
 # XXX: suppress that
 if [ "$bsd" = "yes" ] ; then
   echo "CONFIG_BSD=y" >> $config_host_mak
--- hw/vga.c    2011-10-19 13:54:48.000000000 +0000
+++ hw/vga.c    2012-03-17 21:53:12.000000000 +0000
@@ -29,6 +29,10 @@
 #include "pixel_ops.h"
 #include "qemu-timer.h"

+#ifdef CONFIG_DUMP_PNG
+#include <png.h>
+#endif
+
 //#define DEBUG_VGA
 //#define DEBUG_VGA_MEM
 //#define DEBUG_VGA_REG
@@ -2329,7 +2333,14 @@
                                 int x, int y, int w, int h)
 {
     if (screen_dump_filename) {
-        ppm_save(screen_dump_filename, ds->surface);
+#ifdef CONFIG_DUMP_PNG
+               if (is_png_extension(screen_dump_filename))
+                       png_save(screen_dump_filename, ds->surface);
+               else
+                       ppm_save(screen_dump_filename, ds->surface);
+#else
+               ppm_save(screen_dump_filename, ds->surface);
+#endif
         screen_dump_filename = NULL;
     }
 }
@@ -2342,6 +2353,95 @@
 {
 }

+#ifdef CONFIG_DUMP_PNG
+int is_png_extension(const char * filename)
+{
+    if (!(filename == NULL)) {
+        char * c;
+        for (c = filename;*c != NULL; ++c);
+        c -= 4;
+        if (*c++ == '.' && *c++ == 'p' && *c++ == 'n' && *c == 'g')
+            return 1;
+    }
+    return 0;
+}
+
+int png_save(const char *filename, struct DisplaySurface *ds)
+{
+    FILE *f;
+    uint8_t *d, *d1;
+    uint32_t v;
+    int y, x;
+    uint8_t r, g, b;
+    // int ret;
+
+    f = fopen(filename, "wb");
+    if (!f)
+        return -1;
+
+       /* initialize stuff */
+       png_structp png_ptr;
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+       if (!png_ptr)
+               return -1;
+
+       png_infop info_ptr;
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+               return -1;
+
+       /* write header */
+    if (setjmp(png_jmpbuf(png_ptr)))
+               return -1;
+
+       // bit depth 16
+    png_set_IHDR(png_ptr, info_ptr, ds->width, ds->height,
+                 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+       /* Process ds */
+    png_byte ** row_pointers = png_malloc(png_ptr, ds->height *
sizeof(png_byte *));
+    d1 = ds->data;
+    for(y = 0; y < ds->height; y++) {
+               row_pointers[y] = (png_byte *) png_malloc(png_ptr, 
sizeof(uint8_t)
* ds->width * 3);
+        png_byte * row = row_pointers[y];
+        d = d1;
+        for(x = 0; x < ds->width; x++) {
+            if (ds->pf.bits_per_pixel == 32) {
+                v = *(uint32_t *)d;
+                       }
+            else {
+                v = (uint32_t) (*(uint16_t *)d);
+                       }
+            r = ((v >> ds->pf.rshift) & ds->pf.rmax) * 256 /
+                (ds->pf.rmax + 1);
+            g = ((v >> ds->pf.gshift) & ds->pf.gmax) * 256 /
+                (ds->pf.gmax + 1);
+            b = ((v >> ds->pf.bshift) & ds->pf.bmax) * 256 /
+                (ds->pf.bmax + 1);
+                       *row++ = r;
+                       *row++ = g;
+                       *row++ = b;
+            d += ds->pf.bytes_per_pixel;
+        }
+        d1 += ds->linesize;
+    }
+
+       png_init_io(png_ptr, f);
+       png_set_rows(png_ptr, info_ptr, row_pointers);
+    png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
+
+    /* cleanup heap allocation */
+    for (y=0; y<ds->height; y++)
+        png_free(png_ptr, row_pointers[y]);
+    png_free(png_ptr, row_pointers);
+    fclose(f);
+       return 0;
+}
+#endif
+
 int ppm_save(const char *filename, struct DisplaySurface *ds)
 {
     FILE *f;
--- hw/vga_int.h        2011-10-19 13:54:48.000000000 +0000
+++ hw/vga_int.h        2012-03-17 22:19:38.000000000 +0000
@@ -205,6 +205,10 @@
 void vga_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val);
 void vga_invalidate_scanlines(VGACommonState *s, int y1, int y2);
 int ppm_save(const char *filename, struct DisplaySurface *ds);
+#ifdef CONFIG_DUMP_PNG
+int is_png_extension(const char * filename);
+int png_save(const char *filename, struct DisplaySurface *ds);
+#endif

 void vga_draw_cursor_line_8(uint8_t *d1, const uint8_t *src1,
                             int poffset, int w,