From 28ecbf82ed3024f51be4c87928fd91bacfc15cbc Mon Sep 17 00:00:00 2001
From: Vincent Sanders <vince@kyllikki.org>
Date: Fri, 26 Feb 2021 13:33:08 +0000
Subject: Initial minimal FLTK toolkit implementation

---
 frontends/fltk/layout.cpp | 141 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 frontends/fltk/layout.cpp

(limited to 'frontends/fltk/layout.cpp')

diff --git a/frontends/fltk/layout.cpp b/frontends/fltk/layout.cpp
new file mode 100644
index 000000000..45044307d
--- /dev/null
+++ b/frontends/fltk/layout.cpp
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2021 Vincent Sanders <vince@netsurf-browser.org>
+ *
+ * This file is part of NetSurf, http://www.netsurf-browser.org/
+ *
+ * NetSurf is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * NetSurf 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * \file
+ * Implementation of netsurf layout operations for fltk.
+ */
+
+#include <stddef.h>
+
+extern "C" {
+
+#include "utils/errors.h"
+#include "utils/utf8.h"
+#include "netsurf/layout.h"
+#include "netsurf/plot_style.h"
+
+}
+
+#include "fltk/layout.h"
+
+/**
+ * Measure the width of a string.
+ *
+ * \param[in] fstyle plot style for this text
+ * \param[in] string UTF-8 string to measure
+ * \param[in] length length of string, in bytes
+ * \param[out] width updated to width of string[0..length)
+ * \return NSERROR_OK and width updated or appropriate error
+ *          code on faliure
+ */
+static nserror
+nsfltk_layout_width(const struct plot_font_style *fstyle,
+		    const char *string,
+		    size_t length,
+		    int *width)
+{
+	*width = (fstyle->size * utf8_bounded_length(string, length)) / PLOT_STYLE_SCALE;
+	return NSERROR_OK;
+}
+
+
+/**
+ * Find the position in a string where an x coordinate falls.
+ *
+ * \param[in] fstyle style for this text
+ * \param[in] string UTF-8 string to measure
+ * \param[in] length length of string, in bytes
+ * \param[in] x coordinate to search for
+ * \param[out] char_offset updated to offset in string of actual_x, [0..length]
+ * \param[out] actual_x updated to x coordinate of character closest to x
+ * \return NSERROR_OK and char_offset and actual_x updated or appropriate error code on faliure
+ */
+static nserror
+nsfltk_layout_position(const struct plot_font_style *fstyle,
+		       const char *string,
+		       size_t length,
+		       int x,
+		       size_t *char_offset,
+		       int *actual_x)
+{
+	*char_offset = x / (fstyle->size / PLOT_STYLE_SCALE);
+	if (*char_offset > length)
+		*char_offset = length;
+	*actual_x = *char_offset * (fstyle->size / PLOT_STYLE_SCALE);
+	return NSERROR_OK;
+}
+
+
+/**
+ * Find where to split a string to make it fit a width.
+ *
+ * \param[in] fstyle       style for this text
+ * \param[in] string       UTF-8 string to measure
+ * \param[in] length       length of string, in bytes
+ * \param[in] x            width available
+ * \param[out] char_offset updated to offset in string of actual_x, [1..length]
+ * \param[out] actual_x updated to x coordinate of character closest to x
+ * \return NSERROR_OK or appropriate error code on faliure
+ *
+ * On exit, char_offset indicates first character after split point.
+ *
+ * \note char_offset of 0 must never be returned.
+ *
+ *   Returns:
+ *     char_offset giving split point closest to x, where actual_x <= x
+ *   else
+ *     char_offset giving split point closest to x, where actual_x > x
+ *
+ * Returning char_offset == length means no split possible
+ */
+static nserror
+nsfltk_layout_split(const struct plot_font_style *fstyle,
+		    const char *string,
+		    size_t length,
+		    int x,
+		    size_t *char_offset,
+		    int *actual_x)
+{
+	int c_off = *char_offset = x / (fstyle->size / PLOT_STYLE_SCALE);
+	if (*char_offset > length) {
+		*char_offset = length;
+	} else {
+		while (*char_offset > 0) {
+			if (string[*char_offset] == ' ')
+				break;
+			(*char_offset)--;
+		}
+		if (*char_offset == 0) {
+			*char_offset = c_off;
+			while (*char_offset < length && string[*char_offset] != ' ') {
+				(*char_offset)++;
+			}
+		}
+	}
+	*actual_x = *char_offset * (fstyle->size / PLOT_STYLE_SCALE);
+	return NSERROR_OK;
+}
+
+static struct gui_layout_table layout_table = {
+	.width = nsfltk_layout_width,
+	.position = nsfltk_layout_position,
+	.split = nsfltk_layout_split,
+};
+
+struct gui_layout_table *nsfltk_layout_table = &layout_table;
-- 
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