From 1f787e13a6c75cf12a09fc44d590ba9169c52a71 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Tue, 26 Jun 2018 14:45:15 +0200
Subject: Add fz_snap_selection function to snap selection to
 chars/words/lines.

Updates the input point coordinates, and also returns a quad with
appropriate UI handles.
---
 include/mupdf/fitz/structured-text.h |  9 +++++
 platform/gl/gl-main.c                |  5 +++
 source/fitz/stext-search.c           | 67 ++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/include/mupdf/fitz/structured-text.h b/include/mupdf/fitz/structured-text.h
index 44219f4d..2adfa73a 100644
--- a/include/mupdf/fitz/structured-text.h
+++ b/include/mupdf/fitz/structured-text.h
@@ -152,6 +152,15 @@ int fz_search_stext_page(fz_context *ctx, fz_stext_page *text, const char *needl
 */
 int fz_highlight_selection(fz_context *ctx, fz_stext_page *page, fz_point a, fz_point b, fz_quad *quads, int max_quads);
 
+enum
+{
+	FZ_SELECT_CHARS,
+	FZ_SELECT_WORDS,
+	FZ_SELECT_LINES,
+};
+
+fz_quad fz_snap_selection(fz_context *ctx, fz_stext_page *page, fz_point *ap, fz_point *bp, int mode);
+
 /*
 	fz_copy_selection: Return a newly allocated UTF-8 string with the text for a given selection.
 
diff --git a/platform/gl/gl-main.c b/platform/gl/gl-main.c
index 726de1c0..ee182cdd 100644
--- a/platform/gl/gl-main.c
+++ b/platform/gl/gl-main.c
@@ -489,6 +489,11 @@ static void do_page_selection(void)
 		fz_transform_point(&page_a, &view_page_inv_ctm);
 		fz_transform_point(&page_b, &view_page_inv_ctm);
 
+		if (ui.mod == GLUT_ACTIVE_CTRL)
+			fz_snap_selection(ctx, page_text, &page_a, &page_b, FZ_SELECT_WORDS);
+		else if (ui.mod == GLUT_ACTIVE_CTRL + GLUT_ACTIVE_SHIFT)
+			fz_snap_selection(ctx, page_text, &page_a, &page_b, FZ_SELECT_LINES);
+
 		n = fz_highlight_selection(ctx, page_text, page_a, page_b, hits, nelem(hits));
 
 		glBlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ZERO); /* invert destination color */
diff --git a/source/fitz/stext-search.c b/source/fitz/stext-search.c
index 0805d3dc..14aa002e 100644
--- a/source/fitz/stext-search.c
+++ b/source/fitz/stext-search.c
@@ -180,6 +180,73 @@ fz_enumerate_selection(fz_context *ctx, fz_stext_page *page, fz_point a, fz_poin
 	}
 }
 
+fz_quad
+fz_snap_selection(fz_context *ctx, fz_stext_page *page, fz_point *a, fz_point *b, int mode)
+{
+	fz_stext_block *block;
+	fz_stext_line *line;
+	fz_stext_char *ch;
+	fz_quad handles;
+	int idx, start, end;
+	int pc;
+
+	start = find_closest_in_page(page, *a);
+	end = find_closest_in_page(page, *b);
+
+	if (start > end)
+		idx = start, start = end, end = idx;
+
+	handles.ll = handles.ul = *a;
+	handles.lr = handles.ur = *b;
+
+	idx = 0;
+	for (block = page->first_block; block; block = block->next)
+	{
+		if (block->type != FZ_STEXT_BLOCK_TEXT)
+			continue;
+		for (line = block->u.t.first_line; line; line = line->next)
+		{
+			pc = '\n';
+			for (ch = line->first_char; ch; ch = ch->next)
+			{
+				if (idx <= start)
+				{
+					if (mode == FZ_SELECT_CHARS
+						|| (mode == FZ_SELECT_WORDS && (pc == ' ' || pc == '\n'))
+						|| (mode == FZ_SELECT_LINES && (pc == '\n')))
+					{
+						handles.ll = ch->quad.ll;
+						handles.ul = ch->quad.ul;
+						*a = ch->origin;
+					}
+				}
+				if (idx >= end)
+				{
+					if (mode == FZ_SELECT_CHARS
+						|| (mode == FZ_SELECT_WORDS && (ch->c == ' ')))
+					{
+						handles.lr = ch->quad.ll;
+						handles.ur = ch->quad.ul;
+						*b = ch->origin;
+						return handles;
+					}
+					if (!ch->next)
+					{
+						handles.lr = ch->quad.lr;
+						handles.ur = ch->quad.ur;
+						*b = ch->quad.lr;
+						return handles;
+					}
+				}
+				pc = ch->c;
+				++idx;
+			}
+		}
+	}
+
+	return handles;
+}
+
 /* Highlight selection */
 
 struct highlight
-- 
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