graphics: add graphics viewer for popular image formats

- use stb_image.h to display bmp, jpeg, pmg, gif, targa and other
  popular image formats
- disable text based image converters

Makefile

@@ -155,6 +155,8 @@ ifdef CONFIG_FFMPEG
   LIBS+= -L$(FFMPEG_LIBDIR)/libavcodec -L$(FFMPEG_LIBDIR)/libavformat -lavformat -lavcodec -lz -lpthread
   DEFINES+= -I$(FFMPEG_SRCDIR)/libavcodec -I$(FFMPEG_SRCDIR)/libavformat
   TARGETS+= ffplay$(EXE)
+else
+  OBJS+= stb.o
 endif
 
 ifdef CONFIG_X11
@@ -308,6 +310,7 @@ $(OBJS_DIR)/fbfrender.o: fbfrender.c fbfrender.h libfbf.h
 $(OBJS_DIR)/qe.o: qe.c parser.c qeconfig.h qfribidi.h variables.h
 $(OBJS_DIR)/qfribidi.o: qfribidi.c qfribidi.h
 $(OBJS_DIR)/clang.o: clang.c rust.c swift.c icon.c groovy.c virgil.c
+$(OBJS_DIR)/stb.o: stb.c stb_image.h
 
 $(XOBJS_DIR)/cfb.o: cfb.c cfb.h fbfrender.h
 $(XOBJS_DIR)/charset.o: charset.c unicode_width.h
@@ -316,6 +319,7 @@ $(XOBJS_DIR)/fbfrender.o: fbfrender.c fbfrender.h libfbf.h
 $(XOBJS_DIR)/qe.o: qe.c parser.c qeconfig.h qfribidi.h variables.h
 $(XOBJS_DIR)/qfribidi.o: qfribidi.c qfribidi.h
 $(XOBJS_DIR)/clang.o: clang.c rust.c swift.c icon.c groovy.c virgil.c
+$(XOBJS_DIR)/stb.o: stb.c stb_image.h
 
 $(TOBJS_DIR)/cfb.o: cfb.c cfb.h fbfrender.h
 $(TOBJS_DIR)/charset.o: charset.c unicode_width.h

TODO.org

@@ -1,7 +1,7 @@
 ; TODO list for qemacs
 ;
 ; Author: Charles Gordon
-; Updated: 2017-05-10
+; Updated: 2017-05-15
 
 * Recent bugs and ideas
 
@@ -643,3 +643,10 @@ ssh: should use the host name and get files via scp syntax
 charset: set-eol-type should take a string: auto/binary/dos/unix/mac/0/1/2...
 archive: use window/buffer caption for output description
 files: handle files with embedded spaces
+dired: group symbolic links to directories with directories
+images: filtered scaling
+images: zoom, pan, rotate, describe, peek-color, histogram...
+images: multiview, wallpaper...
+images: use screen aspect-ratio...
+images: display info on modeline
+images: prevent display if not invalid

archive.c

@@ -231,8 +231,8 @@ static CompressType compress_type_array[] = {
     { "sqlite", "SQLite format 3\0", 16, NULL, "sqlite3 $1 .dump", NULL },
     { "bplist", "bplist00", 8, "plist", "plutil -p $1", NULL },
 //    { "bplist", "bplist00", 8, "plist", "plutil -convert xml1 -o - $1", NULL },
-    { "jpeg", NULL, 0, "jpg", "jp2a --height=35 --background=dark $1", NULL, SF_COLOR },
-    { "image", NULL, 0, "bmp", "img2txt -f utf8 $1", NULL, SF_COLOR  },
+//    { "jpeg", NULL, 0, "jpg", "jp2a --height=35 --background=dark $1", NULL, SF_COLOR },
+//    { "image", NULL, 0, "bmp", "img2txt -f utf8 $1", NULL, SF_COLOR  },
     { "pdf", NULL, 0, "pdf", "pstotext $1", NULL },
 };
 

stb.c

@@ -0,0 +1,156 @@
+/*
+ * QEmacs graphics mode for image files
+ *
+ * Copyright (c) 2017 Charlie Gordon.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "qe.h"
+
+#define STB_IMAGE_IMPLEMENTATION
+#define STBI_ASSERT(x)
+#undef malloc
+#undef realloc
+#undef free
+#include "stb_image.h"
+
+/*----------------------------------------------------------------*/
+
+static ModeDef stb_mode;
+
+typedef struct ImageState {
+    QEModeData base;
+
+    QEPicture pic;
+
+    void *stb_image;
+    int stb_x, stb_y, stb_channels;
+
+} ImageState;
+
+/*----------------*/
+
+static inline ImageState *image_get_state(EditState *e, int status)
+{
+    return qe_get_buffer_mode_data(e->b, &stb_mode, status ? e : NULL);
+}
+
+static void image_display(EditState *s) {
+    ImageState *ms = image_get_state(s, 0);
+    QEColor col = qe_styles[QE_STYLE_GUTTER].bg_color;
+
+    if (s->display_invalid) {
+        if (ms && ms->stb_image) {
+            int x0, y0, w, h;
+#if 0
+            /* No scaling */
+            w = min(s->width, ms->pic.width);
+            h = min(s->height, ms->pic.height / s->screen->dpy.yfactor);
+            x0 = (s->width - w) / 2;
+            y0 = (s->height - h) / 2;
+            qe_draw_picture(s->screen, s->xleft + x0, s->ytop + y0, w, h,
+                            &ms->pic, 0, 0, w, h * s->screen->dpy.yfactor,
+                            0, QERGB(128, 128, 128));
+            fill_border(s, x0, y0, w, h, col);
+            put_status(s, "%dx%dx%d",
+                       ms->pic.width, ms->pic.height, ms->stb_channels * 8);
+#else
+            int factor = 1024;
+
+            w = ms->pic.width;
+            h = ms->pic.height / s->screen->dpy.yfactor;
+            /* compute scaling factor for scale up or down */
+            factor = min(4 * 1024, min(s->width * 1024 / w, s->height * 1024 / h));
+            /* Do not scale up on text display */
+            if (factor < 1024 || s->width != s->cols) {
+                w = ((w * factor) + 512) / 1024;
+                h = ((h * factor) + 512) / 1024;
+            }
+            x0 = (s->width - w) / 2;
+            y0 = (s->height - h) / 2;
+            qe_draw_picture(s->screen, s->xleft + x0, s->ytop + y0, w, h,
+                            &ms->pic, 0, 0, ms->pic.width, ms->pic.height,
+                            0, QERGB(128, 128, 128));
+            fill_border(s, x0, y0, w, h, col);
+            put_status(s, "%dx%dx%d",
+                       ms->pic.width, ms->pic.height, ms->stb_channels * 8);
+#endif
+        } else {
+            fill_rectangle(s->screen, s->xleft, s->ytop, s->width, s->height, col);
+        }
+        s->display_invalid = 0;
+    }
+    if (s->qe_state->active_window == s) {
+        /* Update cursor */
+        int xc = s->xleft;
+        int yc = s->ytop;
+        int w = s->char_width;
+        int h = s->line_height;
+        if (s->screen->dpy.dpy_cursor_at) {
+            /* hardware cursor */
+            s->screen->dpy.dpy_cursor_at(s->screen, xc, yc, w, h);
+        } else {
+            xor_rectangle(s->screen, xc, yc, w, h, QERGB(0xFF, 0xFF, 0xFF));
+        }
+    }
+}
+
+static void image_display_hook(EditState *s) {
+    ImageState *ms = image_get_state(s, 0);
+
+    if (ms && !ms->stb_image) {
+        ms->stb_image = stbi_load(s->b->filename,
+                                  &ms->stb_x, &ms->stb_y, &ms->stb_channels, 4);
+        if (ms->stb_image) {
+            ms->pic.width = ms->stb_x;
+            ms->pic.height = ms->stb_y;
+            ms->pic.format = QEBITMAP_FORMAT_BGRA32;
+            ms->pic.data[0] = ms->stb_image;
+            ms->pic.linesize[0] = ms->stb_x * 4;
+        } else {
+            put_status(s, "stbi_load error");
+        }
+    }
+    edit_invalidate(s, 1);
+}
+
+static void image_mode_free(EditBuffer *b, void *state) {
+    ImageState *ms = state;
+
+    if (ms->stb_image) {
+        stbi_image_free(ms->stb_image);
+        ms->stb_image = NULL;
+        ms->pic.data[0] = NULL;
+    }
+}
+
+static ModeDef stb_mode = {
+    .name = "Image file",
+    .alt_name = "stb",
+    .extensions = "bmp|jpg|jpeg|png|tga|psd|gif|hdr|pic|pnm|ppm|pgm",
+    .buffer_instance_size = sizeof(ImageState),
+    .mode_free = image_mode_free,
+    .display_hook = image_display_hook,
+    .display = image_display,
+};
+
+static int stb_init(void)
+{
+    qe_register_mode(&stb_mode, MODEF_VIEW);
+    return 0;
+}
+
+qe_module_init(stb_init);