[ghex/gtk4-port: 10/91] Continue gtk4 port. gtkhex: hex lines appear now.

[Logan Rathbone <larathbone src gnome org>]

commit 9d8f0d0622c0dff62d0887ad4b781b44994a30d8
Author: Logan Rathbone <poprocks gmail com>
Date:   Tue Jan 5 10:59:38 2021 -0500

    Continue gtk4 port. gtkhex: hex lines appear now.

 src/gtkhex.c | 165 +++++++++++++++++++++--------------------------------------
 1 file changed, 59 insertions(+), 106 deletions(-)
---
diff --git a/src/gtkhex.c b/src/gtkhex.c
index f4ee058e..7e253856 100644
--- a/src/gtkhex.c
+++ b/src/gtkhex.c
@@ -262,10 +262,6 @@ get_char_height (GtkHex *gh)
        context = gtk_widget_get_pango_context (GTK_WIDGET(gh));
        metrics = pango_context_get_metrics (context, NULL, NULL);
 
-       g_debug("%s: CHAR_HEIGHT: %d",
-                       __func__,
-                       pango_font_metrics_get_height (metrics));
-
        height =
                PANGO_PIXELS(pango_font_metrics_get_height (metrics));
        
@@ -294,45 +290,6 @@ get_char_width (GtkHex *gh)
        return width;
 }
 
-#if 0
-/* LAR: REWRITE */
-static guint
-get_max_char_width(GtkHex *gh, PangoFontMetrics *font_metrics)
-{
-       /* this is, I guess, a rather dirty trick, but
-          right now i can't think of anything better */
-       guint i;
-       guint maxwidth = 0;
-       PangoRectangle logical_rect;
-       PangoLayout *layout;
-       gchar str[2]; 
-
-       if (char_widths == NULL)
-               char_widths = (gchar*)g_malloc(0x100);
-
-       char_widths[0] = 0;
-
-       layout = gtk_widget_create_pango_layout (GTK_WIDGET (gh), "");
-
-       for(i = 1; i < 0x100; i++) {
-               logical_rect.width = 0;
-               /* Check if the char is displayable. Caused trouble to pango */
-               if (is_displayable((guchar)i)) {
-                       sprintf (str, "%c", (gchar)i);
-                       pango_layout_set_text(layout, str, -1);
-                       pango_layout_get_pixel_extents (layout, NULL, &logical_rect);
-               }
-               char_widths[i] = logical_rect.width;
-       }
-
-       for(i = '0'; i <= 'z'; i++)
-               maxwidth = MAX(maxwidth, char_widths[i]);
-
-       g_object_unref (G_OBJECT (layout));
-       return maxwidth;
-}
-#endif
-
 void
 format_xbyte(GtkHex *gh, gint pos, gchar buf[2]) {
        guint low, high;
@@ -846,68 +803,78 @@ invalidate_offsets (GtkHex *gh,
 }
 
 /*
- * when calling render_*_lines() the imin and imax arguments are the
+ * when calling render_*_lines() the min_lines and max_lines arguments are the
  * numbers of the first and last line TO BE DISPLAYED in the range
  * [0 .. gh->vis_lines-1] AND NOT [0 .. gh->lines]!
  */
 static void
 render_hex_lines (GtkHex *gh,
                   cairo_t *cr,
-                  gint imin,
-                  gint imax)
+                  int min_lines,
+                  int max_lines)
 {
-       GtkWidget *w = gh->xdisp;
-       GdkRGBA bg_color;
-       GdkRGBA fg_color;
+       GtkWidget *widget = gh->xdisp;
        GtkAllocation allocation;
        GtkStateFlags state;
        GtkStyleContext *context;
-       gint i, cursor_line;
-       gint xcpl = gh->cpl*2 + gh->cpl/gh->group_type;
-       gint frm_len, tmp;
+       int cursor_line;
+       int xcpl = gh->cpl * 2 + gh->cpl / gh->group_type;
+       int frm_len;
 
-       g_return_if_fail (gtk_widget_get_realized(GTK_WIDGET (gh)));
-       g_return_if_fail (gh->cpl);
-
-       context = gtk_widget_get_style_context (w);
-       state = gtk_widget_get_state_flags (w);
+       g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET(gh)));
+       g_return_if_fail (gh->cpl > 0);
 
-       /* gtk_render_background? */
-//     gtk_style_context_get_background_color (context, state, &bg_color);
-//     // API CHANGE
-       //gtk_style_context_get_color (context, state, &fg_color);
-       gtk_style_context_get_color (context, &fg_color);
+       TEST_DEBUG_FUNCTION_START
 
+       context = gtk_widget_get_style_context (widget);
+       state = gtk_widget_get_state_flags (widget);
        cursor_line = gh->cursor_pos / gh->cpl - gh->top_line;
+       gtk_widget_get_allocation (widget, &allocation);
 
-       gtk_widget_get_allocation(w, &allocation);
-//     gdk_cairo_set_source_rgba (cr, &bg_color);
-       cairo_rectangle (cr, 0, imin * gh->char_height, allocation.width, (imax - imin + 1) * 
gh->char_height);
-       cairo_fill (cr);
-  
-       imax = MIN(imax, gh->vis_lines);
-       imax = MIN(imax, gh->lines);
+       /* render background. */
+       gtk_render_background (context, cr,
+                       /* x: */                0,
+                       /* y: */                min_lines * gh->char_height,
+                       /* width: */    allocation.width,
+                       /* height: */   (max_lines - min_lines + 1) * gh->char_height);
 
-       gdk_cairo_set_source_rgba (cr, &fg_color);
+       max_lines = MIN(max_lines, gh->vis_lines);
+       max_lines = MIN(max_lines, gh->lines);
 
+       /* FIXME - I have no idea what this does. It's too early in the morning
+        * and the coffee hasn't kicked in yet. Maybe break this down / comment
+        * it to make it clearer?
+        */
        frm_len = format_xblock (gh, gh->disp_buffer,
-                       (gh->top_line+imin)*gh->cpl,
-                       MIN((gh->top_line+imax+1)*gh->cpl,
+                       (gh->top_line+min_lines)*gh->cpl,
+                       MIN((gh->top_line+max_lines+1)*gh->cpl,
                                gh->document->file_size) );
        
-       for (i = imin; i <= imax; i++) {
-               tmp = (gint)frm_len - (gint)((i - imin)*xcpl);
+       for (int i = min_lines; i <= max_lines; i++) {
+               int tmp = frm_len - ((i - min_lines) * xcpl);
+
                if(tmp <= 0)
                        break;
 
                render_hex_highlights (gh, cr, i);
-               cairo_move_to (cr, 0, i * gh->char_height);
-               pango_layout_set_text (gh->xlayout, gh->disp_buffer + (i - imin) * xcpl, MIN(xcpl, tmp));
-               pango_cairo_show_layout (cr, gh->xlayout);
+
+               /* Set pango layout to the line of hex to render. */
+               // FIXME - make this understandable.
+               pango_layout_set_text (gh->xlayout,
+                               gh->disp_buffer + (i - min_lines) * xcpl,
+                               MIN(xcpl, tmp));
+
+               gtk_render_layout (context, cr,
+                               /* x: */ 0,
+                               /* y: */ i * gh->char_height,
+                               gh->xlayout);
        }
        
-       if((cursor_line >= imin) && (cursor_line <= imax) && (gh->cursor_shown))
+       if ( (cursor_line >= min_lines) && (cursor_line <= max_lines) &&
+                       (gh->cursor_shown) )
+       {
                render_xc (gh, cr);
+       }
 }
 
 static void
@@ -971,8 +938,8 @@ render_ascii_lines (GtkHex *gh,
 static void
 render_offsets (GtkHex *gh,
                 cairo_t *cr,
-                gint min_lines,
-                gint max_lines)
+                int min_lines,
+                int max_lines)
 {
        GtkWidget *widget = gh->offsets;
        GdkRGBA fg_color;
@@ -980,55 +947,40 @@ render_offsets (GtkHex *gh,
        GtkStateFlags state;
        GtkStyleContext *context;
        /* offset chars (8) + 1 (null terminator) */
-       gchar offstr[9];
+       char offstr[9];
 
        TEST_DEBUG_FUNCTION_START 
 
-       g_debug("%s: char_height: %u",
-                       __func__, gh->char_height);
-
        g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (gh)));
 
        context = gtk_widget_get_style_context (widget);
        state = gtk_widget_get_state_flags (widget);
 
-//     API CHANGE - FIXME - see if even needed. Guessing not.
-//     gtk_style_context_get_color (context, state, &fg_color);
-       gtk_style_context_get_color (context, &fg_color);
-
        gtk_widget_get_allocation(widget, &allocation);
 
        /* render background. */
-       g_debug("%s: RENDERING BACKGROUND", __func__);
        gtk_render_background (context, cr,
                        /* x: */                0,
                        /* y: */                min_lines * gh->char_height,
                        /* width: */    allocation.width,
                        /* height: */   (max_lines - min_lines + 1) * gh->char_height);
-
   
        /* update max_lines and min_lines - FIXME this is from original code -
         * why?? - test and see. */
        max_lines = MIN(max_lines, gh->vis_lines);
        max_lines = MIN(max_lines, gh->lines - gh->top_line - 1);
 
-       gdk_cairo_set_source_rgba (cr, &fg_color);
-       
        for (int i = min_lines; i <= max_lines; i++) {
                /* generate offset string and place in temporary buffer */
                sprintf(offstr, "%08X",
                                (gh->top_line + i) * gh->cpl + gh->starting_offset);
 
-               // LAR - TEST FOR GTK4
+               /* build pango layout for offset line; draw line with gtk. */
                pango_layout_set_text (gh->olayout, offstr, 8);
                gtk_render_layout (context, cr,
                                /* x: */ 0,
                                /* y: */ i * gh->char_height,
                                gh->olayout);
-
-               // OLD CODE:
-//             cairo_move_to (cr, 0, i * gh->char_height);
-//             pango_cairo_show_layout (cr, gh->olayout);
        }
 }
 
@@ -2608,19 +2560,18 @@ gtk_hex_init(GtkHex *gh)
        gh->char_width = get_char_width(gh);
        gh->char_height = get_char_height(gh);
 
-//     gh->char_width = get_max_char_width(gh, gh->disp_font_metrics);
-//
-//     gh->char_height = PANGO_PIXELS (pango_font_metrics_get_ascent (gh->disp_font_metrics)) +
-//             PANGO_PIXELS (pango_font_metrics_get_descent (gh->disp_font_metrics)) + 2;
-       
        // GTK4 - TEST - DON'T KNOW IF NECESSARY FOR KEYBOARD STUFF - FIXME
        gtk_widget_set_can_focus(GTK_WIDGET(gh), TRUE);
-       // API CHANGE
+
+       // API CHANGE - FIXME REWRITE.
 //     gtk_widget_set_events(GTK_WIDGET(gh), GDK_KEY_PRESS_MASK);
-       
-       context = gtk_widget_get_style_context (GTK_WIDGET (gh));
 
+       /* Init CSS */
        // LAR - FIXME - made some fixes, but tweak etc.
+
+       context = gtk_widget_get_style_context (GTK_WIDGET (gh));
+
+       /* set up a provider so we can feed CSS through C code. */
        provider = gtk_css_provider_new ();
        gtk_css_provider_load_from_data (GTK_CSS_PROVIDER (provider),
                                                                        CSS_NAME " {\n"
@@ -2630,6 +2581,8 @@ gtk_hex_init(GtkHex *gh)
                                         "   border-width: 1px;\n"
                                         "   padding: 1px;\n"
                                         "}\n", -1);
+
+       /* add the provider to our widget's style context. */
        gtk_style_context_add_provider (context,
                                        GTK_STYLE_PROVIDER (provider),
                                        GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
@@ -2903,7 +2856,7 @@ guchar gtk_hex_get_byte(GtkHex *gh, guint offset) {
 }
 
 /*
- * sets data group type (see GROUP_* defines in gtkhex.h)
+ * sets data group type (see GROUP_* defines at top of file)
  */
 void gtk_hex_set_group_type(GtkHex *gh, guint gt) {
        GtkAllocation allocation;