Implement text selection

5 files changed, 180 insertions, 31 deletions

diff --git a/src/frame.c b/src/frame.c
index d654965..36a7983 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1,7 +1,7 @@
 /*
  * frame.c
  *
- * Copyright © 2013-2016 Thomas White <taw@bitwiz.org.uk>
+ * Copyright © 2013-2017 Thomas White <taw@bitwiz.org.uk>
  *
  * This file is part of Colloquium.
  *
@@ -270,7 +270,8 @@ struct frame *find_frame_with_scblocks(struct frame *fr, SCBlock *scblocks)
 }
 
 
-void wrap_paragraph(Paragraph *para, PangoContext *pc, double w)
+void wrap_paragraph(Paragraph *para, PangoContext *pc, double w,
+                    size_t sel_start, size_t sel_end)
 {
 	size_t total_len = 0;
 	int i;
@@ -327,6 +328,15 @@ void wrap_paragraph(Paragraph *para, PangoContext *pc, double w)
 
 	}
 
+	/* Add attributes for selected text */
+	if ( sel_start > 0 || sel_end > 0 ) {
+		PangoAttribute *attr;
+		attr = pango_attr_background_new(42919, 58853, 65535);
+		attr->start_index = sel_start;
+		attr->end_index = sel_end;
+		pango_attr_list_insert(attrs, attr);
+	}
+
 	if ( para->layout == NULL ) {
 		para->layout = pango_layout_new(pc);
 	}
@@ -593,10 +603,30 @@ static size_t text_para_pos(Paragraph *para, double x, double y, int *ptrail)
 }
 
 
-int find_cursor(struct frame *fr, double x, double y,
-                int *ppara, size_t *ppos, int *ptrail)
+void sort_positions(struct edit_pos *a, struct edit_pos *b)
+{
+	if ( a->para > b->para ) {
+		size_t tpos;
+		int tpara, ttrail;
+		tpara = b->para;   tpos = b->pos;  ttrail = b->trail;
+		b->para = a->para;  b->pos = a->pos;  b->trail = a->trail;
+		a->para = tpara;    a->pos = tpos;    a->trail = ttrail;
+	}
+
+	if ( (a->para == b->para) && (a->pos > b->pos) )
+	{
+		size_t tpos = b->pos;
+		int ttrail = b->trail;
+		b->pos = a->pos;  b->trail = a->trail;
+		a->pos = tpos;    a->trail = ttrail;
+	}
+}
+
+
+int find_cursor_2(struct frame *fr, double x, double y,
+                  struct edit_pos *pos)
 {
-	double pos = fr->pad_t;
+	double pad = fr->pad_t;
 	int i;
 
 	if ( fr == NULL ) {
@@ -605,20 +635,20 @@ int find_cursor(struct frame *fr, double x, double y,
 	}
 
 	for ( i=0; i<fr->n_paras; i++ ) {
-		double npos = pos + fr->paras[i]->height;
+		double npos = pad + fr->paras[i]->height;
 		if ( npos > y ) {
-			*ppara = i;
+			pos->para = i;
 			if ( fr->paras[i]->type == PARA_TYPE_TEXT ) {
-				*ppos = text_para_pos(fr->paras[i],
+				pos->pos = text_para_pos(fr->paras[i],
 				          x - fr->pad_l - fr->paras[i]->space[0],
-				          y - pos - fr->paras[i]->space[2],
-				          ptrail);
+				          y - pad - fr->paras[i]->space[2],
+				          &pos->trail);
 			} else {
-				*ppos = 0;
+				pos->pos = 0;
 			}
 			return 0;
 		}
-		pos = npos;
+		pad = npos;
 	}
 
 	if ( fr->n_paras == 0 ) {
@@ -627,10 +657,24 @@ int find_cursor(struct frame *fr, double x, double y,
 	}
 
 	/* Pretend it's in the last paragraph */
-	pos -= fr->paras[fr->n_paras-1]->height;
-	*ppara = fr->n_paras - 1;
-	*ppos = text_para_pos(fr->paras[fr->n_paras-1],
-	                      x - fr->pad_l, y - pos, ptrail);
+	pad -= fr->paras[fr->n_paras-1]->height;
+	pos->para = fr->n_paras - 1;
+	pos->pos = text_para_pos(fr->paras[fr->n_paras-1],
+	                         x - fr->pad_l, y - pad, &pos->trail);
+	return 0;
+}
+
+
+int find_cursor(struct frame *fr, double x, double y,
+                int *ppara, size_t *ppos, int *ptrail)
+{
+	struct edit_pos p;
+	int r;
+	r = find_cursor_2(fr, x, y, &p);
+	if ( r ) return r;
+	*ppara = p.para;
+	*ppos = p.pos;
+	*ptrail = p.trail;
 	return 0;
 }
 
@@ -1092,8 +1136,8 @@ static SCBlock *split_text_paragraph(struct frame *fr, int pn, size_t pos,
 	pnew->open = para->open;
 	para->open = 0;
 
-	wrap_paragraph(para, pc, fr->w - fr->pad_l - fr->pad_r);
-	wrap_paragraph(pnew, pc, fr->w - fr->pad_l - fr->pad_r);
+	wrap_paragraph(para, pc, fr->w - fr->pad_l - fr->pad_r, 0, 0);
+	wrap_paragraph(pnew, pc, fr->w - fr->pad_l - fr->pad_r, 0, 0);
 
 	return sc_block_next(rr->scblock);
 }
diff --git a/src/frame.h b/src/frame.h
index 4f8be33..787a2ec 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -1,7 +1,7 @@
 /*
  * frame.h
  *
- * Copyright © 2013-2016 Thomas White <taw@bitwiz.org.uk>
+ * Copyright © 2013-2017 Thomas White <taw@bitwiz.org.uk>
  *
  * This file is part of Colloquium.
  *
@@ -58,6 +58,15 @@ enum para_type
 
 typedef struct _paragraph Paragraph;
 
+
+struct edit_pos
+{
+	int para;
+	size_t pos;
+	int trail;
+};
+
+
 struct frame
 {
 	struct frame            **children;
@@ -135,13 +144,19 @@ extern void add_image_para(struct frame *fr, SCBlock *scblock,
                            const char *filename,
                            double w, double h, int editable);
 
-extern void wrap_paragraph(Paragraph *para, PangoContext *pc, double w);
+extern void wrap_paragraph(Paragraph *para, PangoContext *pc, double w,
+                           size_t sel_start, size_t sel_end);
 
 extern size_t end_offset_of_para(struct frame *fr, int pn);
 
 extern int find_cursor(struct frame *fr, double x, double y,
                        int *ppara, size_t *ppos, int *ptrail);
 
+extern int find_cursor_2(struct frame *fr, double x, double y,
+                         struct edit_pos *pos);
+
+extern void sort_positions(struct edit_pos *a, struct edit_pos *b);
+
 extern int get_para_highlight(struct frame *fr, int cursor_para,
                               double *cx, double *cy, double *cw, double *ch);
 
diff --git a/src/render.c b/src/render.c
index a8ff7ea..f87c5b9 100644
--- a/src/render.c
+++ b/src/render.c
@@ -1,7 +1,7 @@
 /*
  * render.c
  *
- * Copyright © 2013-2016 Thomas White <taw@bitwiz.org.uk>
+ * Copyright © 2013-2017 Thomas White <taw@bitwiz.org.uk>
  *
  * This file is part of Colloquium.
  *
@@ -151,7 +151,7 @@ void wrap_frame(struct frame *fr, PangoContext *pc)
 	w = fr->w - fr->pad_l - fr->pad_r;
 
 	for ( i=0; i<fr->n_paras; i++ ) {
-		wrap_paragraph(fr->paras[i], pc, w);
+		wrap_paragraph(fr->paras[i], pc, w, 0, 0);
 	}
 }
 
diff --git a/src/sc_editor.c b/src/sc_editor.c
index fe52ce8..4d9a817 100644
--- a/src/sc_editor.c
+++ b/src/sc_editor.c
@@ -675,7 +675,7 @@ static void insert_text(char *t, SCEditor *e)
 		insert_text_in_paragraph(para, off, t);
 		wrap_paragraph(para, NULL,
 		               e->cursor_frame->w - e->cursor_frame->pad_l
-		                            - e->cursor_frame->pad_r);
+		                            - e->cursor_frame->pad_r, 0, 0);
 		if ( e->flow ) update_size(e);
 
 		cursor_moveh(e->cursor_frame, &e->cursor_para,
@@ -733,7 +733,8 @@ static void do_backspace(struct frame *fr, SCEditor *e)
 	             &e->cursor_trail, -1);
 	if ( e->cursor_para != old_para ) {
 		merge_paragraphs(e->cursor_frame, e->cursor_para);
-		wrap_paragraph(e->cursor_frame->paras[new_para], NULL, wrapw);
+		wrap_paragraph(e->cursor_frame->paras[new_para], NULL, wrapw,
+		               0, 0);
 	} else {
 
 		size_t offs_new, offs_old;
@@ -743,7 +744,7 @@ static void do_backspace(struct frame *fr, SCEditor *e)
 		offs_old = pos_trail_to_offset(para, old_pos, old_trail);
 
 		delete_text_in_paragraph(para, offs_new, offs_old);
-		wrap_paragraph(para, NULL, wrapw);
+		wrap_paragraph(para, NULL, wrapw, 0, 0);
 
 	}
 
@@ -962,7 +963,69 @@ static void check_paragraph(struct frame *fr, PangoContext *pc,
 	}
 
 	add_run(para, scblocks, NULL, 0, 0, fr->fontdesc, fr->col);
-	wrap_paragraph(para, pc, fr->w - fr->pad_l - fr->pad_r);
+	wrap_paragraph(para, pc, fr->w - fr->pad_l - fr->pad_r, 0, 0);
+}
+
+
+static void rewrap_paragraph_range(struct frame *fr, int a, int b,
+                                   struct edit_pos sel_start,
+                                   struct edit_pos sel_end,
+                                   int sel_active)
+{
+	int i;
+	int sel_s, sel_e;
+	Paragraph *para;
+
+	if ( a > b ) {
+		int t = a;
+		a = b; b = t;
+	}
+
+	if ( fr->paras == NULL ) return;
+
+	sort_positions(&sel_start, &sel_end);
+
+	para = fr->paras[sel_start.para];
+	sel_s = pos_trail_to_offset(para, sel_start.pos, sel_start.trail);
+	para = fr->paras[sel_end.para];
+	sel_e = pos_trail_to_offset(para, sel_end.pos, sel_end.trail);
+
+	for ( i=a; i<=b; i++ ) {
+		size_t srt, end;
+		if ( sel_active ) {
+			if ( i == sel_start.para ) {
+				srt = sel_s;
+			} else {
+				srt = 0;
+			}
+			if ( i == sel_end.para ) {
+				end = sel_e;
+			} else {
+				end = G_MAXUINT;
+			}
+			if ( i > sel_start.para && i < sel_end.para ) {
+				end = G_MAXUINT;
+			}
+		} else {
+			srt = 0;
+			end = 0;
+		}
+		wrap_paragraph(fr->paras[i], NULL,
+		               fr->w - fr->pad_l - fr->pad_r, srt, end);
+	}
+}
+
+
+static void unset_selection(SCEditor *e)
+{
+	int a, b;
+	a = e->sel_start.para;
+	b = e->sel_end.para;
+	if ( a > b ) {
+		a = e->sel_end.para;
+		b = e->sel_start.para;
+	}
+	rewrap_paragraph_range(e->top, a, b, e->sel_start, e->sel_end, 0);
 }
 
 
@@ -1029,6 +1092,12 @@ static gboolean button_press_sig(GtkWidget *da, GdkEventButton *event,
 			if ( fr->resizable ) {
 				e->drag_status = DRAG_STATUS_COULD_DRAG;
 				e->drag_reason = DRAG_REASON_MOVE;
+			} else {
+				e->drag_status = DRAG_STATUS_COULD_DRAG;
+				e->drag_reason = DRAG_REASON_TEXTSEL;
+				unset_selection(e);
+				find_cursor_2(clicked, x-fr->x, y-fr->y,
+				              &e->sel_start);
 			}
 
 		}
@@ -1047,8 +1116,11 @@ static gboolean button_press_sig(GtkWidget *da, GdkEventButton *event,
 	} else {
 
 		/* Clicked an existing frame, no immediate dragging */
-		e->drag_status = DRAG_STATUS_NONE;
-		e->drag_reason = DRAG_REASON_NONE;
+		e->drag_status = DRAG_STATUS_COULD_DRAG;
+		e->drag_reason = DRAG_REASON_TEXTSEL;
+		unset_selection(e);
+		find_cursor_2(clicked, x-clicked->x, y-clicked->y,
+		              &e->sel_start);
 		e->selection = clicked;
 		e->cursor_frame = clicked;
 		if ( clicked == e->top ) {
@@ -1075,7 +1147,7 @@ static gboolean motion_sig(GtkWidget *da, GdkEventMotion *event,
 	gdouble x, y;
 
 	x = event->x - e->border_offs_x;
-	y = event->y - e->border_offs_y;
+	y = event->y - e->border_offs_y + e->scroll_pos;
 
 	if ( e->drag_status == DRAG_STATUS_COULD_DRAG ) {
 
@@ -1113,6 +1185,16 @@ static gboolean motion_sig(GtkWidget *da, GdkEventMotion *event,
 		sc_editor_redraw(e);
 		break;
 
+		case DRAG_REASON_TEXTSEL :
+		unset_selection(e);
+		find_cursor_2(fr, x-fr->x, y-fr->y, &e->sel_end);
+		rewrap_paragraph_range(fr, e->sel_start.para, e->sel_end.para,
+		                       e->sel_start, e->sel_end, 1);
+		find_cursor(fr, x-fr->x, y-fr->y, &e->cursor_para,
+		            &e->cursor_pos, &e->cursor_trail);
+		sc_editor_redraw(e);
+		break;
+
 	}
 
 	gdk_event_request_motions(event);
@@ -1237,6 +1319,10 @@ static gboolean button_release_sig(GtkWidget *da, GdkEventButton *event,
 		do_resize(e, e->box_x, e->box_y, e->box_width, e->box_height);
 		break;
 
+		case DRAG_REASON_TEXTSEL :
+		/* Do nothing (text is already selected) */
+		break;
+
 	}
 
 	e->drag_reason = DRAG_REASON_NONE;
diff --git a/src/sc_editor.h b/src/sc_editor.h
index e5e415d..4b55e0e 100644
--- a/src/sc_editor.h
+++ b/src/sc_editor.h
@@ -1,7 +1,7 @@
 /*
  * sc_editor.h
  *
- * Copyright © 2014-2016 Thomas White <taw@bitwiz.org.uk>
+ * Copyright © 2014-2017 Thomas White <taw@bitwiz.org.uk>
  *
  * This file is part of Colloquium.
  *
@@ -59,7 +59,8 @@ enum drag_reason
 	DRAG_REASON_CREATE,
 	DRAG_REASON_IMPORT,
 	DRAG_REASON_RESIZE,
-	DRAG_REASON_MOVE
+	DRAG_REASON_MOVE,
+	DRAG_REASON_TEXTSEL
 };
 
 
@@ -142,6 +143,9 @@ struct _sceditor
 	enum drag_reason     drag_reason;
 	enum drag_status     drag_status;
 	enum corner          drag_corner;
+	int                  sel_active;
+	struct edit_pos      sel_start; /* Where the user dragged from */
+	struct edit_pos      sel_end;
 
 	/* Stuff to do with drag and drop import of "content" */
 	int                  drag_preview_pending;