commit 05e4c9d086c3db2ad726f789cee1b9f8d7ea07b9
parent 93dfd2ced8dc537d2a667857f39b07bcc8307892
Author: lumidify <nobody@lumidify.org>
Date:   Wed,  6 May 2020 20:59:25 +0200
Start work on textedit
Diffstat:
| M | NOTES |  |  | 6 | ++++++ | 
| M | test1.c |  |  | 3 | ++- | 
| M | text-hb.c |  |  | 8 | +++++++- | 
| A | textedit_wip.c |  |  | 798 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | 
| A | textedit_wip.h |  |  | 175 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | 
5 files changed, 988 insertions(+), 2 deletions(-)
diff --git a/NOTES b/NOTES
@@ -24,3 +24,9 @@ an abstract LtkTextLine that can be rendered without
 caring about such details. This would easily allow
 one file for shaping with harfbuzz, one for just
 using the regular kerning with stb_truetype, etc.
+
+Text editor tags (highlight, etc.) - just store in
+linked list or something similar in sorted order;
+when looping over characters to draw them, keep a
+pointer to the current tag, then change it to the
+next one if the end of its bound comes
diff --git a/test1.c b/test1.c
@@ -34,7 +34,8 @@ int main(int argc, char *argv[])
 	LtkButton *button3 = ltk_create_button(window1, "I'm a button!", NULL);
 	ltk_grid_widget(button3, grid1, 1, 0, 1, 1, LTK_STICKY_TOP | LTK_STICKY_BOTTOM | LTK_STICKY_RIGHT);
 	//LtkButton *button4 = ltk_create_button(window1, "I'm a button!", NULL);
-	LtkButton *button4 = ltk_create_button(window1, "ہمارے بارے میں blablabla", NULL);
+	//LtkButton *button4 = ltk_create_button(window1, "ہمارے بارے میں blablabla", NULL);
+	LtkButton *button4 = ltk_create_button(window1, "پَیدایش", NULL);
 	ltk_grid_widget(button4, grid1, 1, 1, 1, 1, LTK_STICKY_LEFT | LTK_STICKY_BOTTOM);
 	ltk_mainloop();
 }
diff --git a/text-hb.c b/text-hb.c
@@ -500,7 +500,7 @@ ltk_create_text_segment(LtkTextManager *tm, uint32_t *text, unsigned int len, ui
 	hb_direction_t dir = hb_script_get_horizontal_direction(script);
 	hb_buffer_set_direction(buf, dir);
 	hb_buffer_set_script(buf, script);
-	hb_buffer_add_codepoints(buf, ts->str, len, 0, len);
+	hb_buffer_add_codepoints(buf, ts->str, len, 1, len-1);
 	/* According to https://harfbuzz.github.io/the-distinction-between-levels-0-and-1.html
 	 * this should be level 1 clustering instead of level 0 */
 	hb_buffer_set_cluster_level(buf, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
@@ -511,11 +511,16 @@ ltk_create_text_segment(LtkTextManager *tm, uint32_t *text, unsigned int len, ui
 	float scale = stbtt_ScaleForMappingEmToPixels(&font->info, size);
 	LtkGlyph *last_glyph = NULL;
 
+	/* FIXME: read https://harfbuzz.github.io/harfbuzz-hb-buffer.html#hb-glyph-position-t-struct */
+
 	int x_min = INT_MAX, x_max = INT_MIN, y_min = INT_MAX, y_max = INT_MIN;
 	int x_abs = 0, y_abs = 0, x1_abs, y1_abs, x2_abs, y2_abs;
 	/* magic, do not touch */
 	LtkGlyph *glyph;
 	for (int i = 0; i < text_len; i++) {
+		if (len == 7) {
+			printf("%d\n", ginf[i].cluster);
+		}
 		gi = &ginf[i];
 		gp = &gpos[i];
 		glyph = malloc(sizeof(LtkGlyph));
@@ -572,6 +577,7 @@ ltk_create_text_segment(LtkTextManager *tm, uint32_t *text, unsigned int len, ui
 	ts->y_max = y_max;
 
 	font->refs++;
+	/* FIXME: destroy hb_buffer */
 
 	return ts;
 }
diff --git a/textedit_wip.c b/textedit_wip.c
@@ -0,0 +1,798 @@
+/*
+ * This file is part of the Lumidify ToolKit (LTK)
+ * Copyright (c) 2017, 2018, 2020 lumidify <nobody@lumidify.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <limits.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include "stb_truetype.h" /* http://nothings.org/stb/stb_truetype.h */
+#include <fontconfig/fontconfig.h>
+#include "khash.h"
+#include <fribidi.h>
+#include <harfbuzz/hb.h>
+#include <harfbuzz/hb-ot.h>
+#include "text-hb.h"
+#include "ltk.h"
+
+extern Ltk *ltk_global;
+
+/* These unicode routines are taken from
+ * https://github.com/JeffBezanson/cutef8 */
+
+/* is c the start of a utf8 sequence? */
+#define isutf(c) (((c)&0xC0)!=0x80)
+
+static const uint32_t offsetsFromUTF8[6] = {
+    0x00000000UL, 0x00003080UL, 0x000E2080UL,
+    0x03C82080UL, 0xFA082080UL, 0x82082080UL
+};
+
+/* next character without NUL character terminator */
+uint32_t u8_nextmemchar(const char *s, size_t *i)
+{
+    uint32_t ch = 0;
+    size_t sz = 0;
+    do {
+        ch <<= 6;
+        ch += (unsigned char)s[(*i)++];
+        sz++;
+    } while (!isutf(s[*i]));
+    ch -= offsetsFromUTF8[sz-1];
+
+    return ch;
+}
+
+/* number of characters in NUL-terminated string */
+size_t u8_strlen(const char *s)
+{
+    size_t count = 0;
+    size_t i = 0, lasti;
+
+    while (1) {
+        lasti = i;
+        while (s[i] > 0)
+            i++;
+        count += (i-lasti);
+        if (s[i++]==0) break;
+        (void)(isutf(s[++i]) || isutf(s[++i]) || ++i);
+        count++;
+    }
+    return count;
+}
+
+size_t u8_wc_toutf8(char *dest, uint32_t ch)
+{
+    if (ch < 0x80) {
+        dest[0] = (char)ch;
+        return 1;
+    }
+    if (ch < 0x800) {
+        dest[0] = (ch>>6) | 0xC0;
+        dest[1] = (ch & 0x3F) | 0x80;
+        return 2;
+    }
+    if (ch < 0x10000) {
+        dest[0] = (ch>>12) | 0xE0;
+        dest[1] = ((ch>>6) & 0x3F) | 0x80;
+        dest[2] = (ch & 0x3F) | 0x80;
+        return 3;
+    }
+    if (ch < 0x110000) {
+        dest[0] = (ch>>18) | 0xF0;
+        dest[1] = ((ch>>12) & 0x3F) | 0x80;
+        dest[2] = ((ch>>6) & 0x3F) | 0x80;
+        dest[3] = (ch & 0x3F) | 0x80;
+        return 4;
+    }
+    return 0;
+}
+
+LtkTextManager *
+ltk_init_text(char *font_name)
+{
+	LtkTextManager *tm = malloc(sizeof(LtkTextManager));
+	if (!tm) {
+		(void)printf("Memory exhausted when trying to create text manager.");
+		exit(1);
+	}
+	tm->font_paths = kh_init(fontid);
+	tm->font_cache = kh_init(fontstruct);
+	tm->glyph_cache = kh_init(glyphcache);
+	tm->font_id_cur = 0;
+	ltk_load_default_font(tm, font_name);
+
+	return tm;
+}
+
+void
+ltk_destroy_text_manager(LtkTextManager *tm)
+{
+	int k;
+
+	kh_destroy(fontid, tm->font_paths);
+
+	for (k = kh_begin(tm->font_cache); k != kh_end(tm->font_cache); k++) {
+		if (kh_exist(tm->font_cache, k)) {
+			ltk_destroy_font(kh_value(tm->font_cache, k));
+		}
+	}
+	kh_destroy(fontstruct, tm->font_cache);
+
+	for (k = kh_begin(tm->glyph_cache); k != kh_end(tm->glyph_cache); k++) {
+		if (kh_exist(tm->glyph_cache, k)) {
+			ltk_destroy_glyph_cache(kh_value(tm->glyph_cache, k));
+		}
+	}
+	kh_destroy(glyphcache, tm->glyph_cache);
+
+	free(tm);
+}
+
+LtkGlyphInfo *
+ltk_create_glyph_info(LtkFont *font, unsigned int id, float scale)
+{
+	LtkGlyphInfo *glyph = malloc(sizeof(LtkGlyphInfo));
+	if (!glyph) {
+		(void)printf("Out of memory!\n");
+		exit(1);
+	}
+	
+	glyph->id = id;
+	glyph->refs = 0;
+	glyph->alphamap = stbtt_GetGlyphBitmap(
+		&font->info, scale, scale, id, &glyph->w,
+		&glyph->h, &glyph->xoff, &glyph->yoff
+	);
+
+	return glyph;
+}
+
+void
+ltk_destroy_glyph_info(LtkGlyphInfo *gi)
+{
+	free(gi->alphamap);
+	free(gi);
+}
+
+LtkGlyphInfo *
+ltk_get_glyph_info(LtkFont *font, unsigned int id, float scale, khash_t(glyphinfo) *cache)
+{
+	int ret;
+	khint_t k;
+	LtkGlyphInfo *glyph;
+	k = kh_get(glyphinfo, cache, id);
+	if (k == kh_end(cache)) {
+		glyph = ltk_create_glyph_info(font, id, scale);
+		/* FIXME: error checking with ret */
+		k = kh_put(glyphinfo, cache, id, &ret);
+		kh_value(cache, k) = glyph;
+	} else {
+		glyph = kh_value(cache, k);
+	}
+
+	return glyph;
+}
+
+khint_t
+ltk_create_glyph_cache(LtkTextManager *tm, uint16_t font_id, uint16_t font_size)
+{
+	khash_t(glyphinfo) *cache = kh_init(glyphinfo);
+	int ret;
+	khint_t k;
+	/* I guess I can just ignore ret for now */
+	k = kh_put(glyphcache, tm->glyph_cache, font_id << 16 + font_size, &ret);
+	kh_value(tm->glyph_cache, k) = cache;
+
+	return k;
+}
+
+void
+ltk_destroy_glyph_cache(khash_t(glyphinfo) *cache)
+{
+	int k;
+	for (k = kh_begin(cache); k != kh_end(cache); k++) {
+		if (kh_exist(cache, k)) {
+			ltk_destroy_glyph_info(kh_value(cache, k));
+		}
+	}
+	kh_destroy(glyphinfo, cache);
+}
+
+void
+ltk_load_default_font(LtkTextManager *tm, char *name)
+{
+	FcPattern *match;
+	FcResult result;
+	char *file;
+	int index;
+	uint16_t font;
+
+	tm->fcpattern = FcNameParse(name);
+	FcPatternAddString(tm->fcpattern, FC_FONTFORMAT, "truetype");
+	FcConfigSubstitute(NULL, tm->fcpattern, FcMatchPattern);
+	FcDefaultSubstitute(tm->fcpattern);
+	match = FcFontMatch(NULL, tm->fcpattern, &result);
+
+	FcPatternGetString (match, FC_FILE, 0, (FcChar8 **) &file);
+	/* FIXME: Why is index never used? This is the index within the font file,
+	   so it might be important, although I'm not sure if stb_truetype even
+	   supports it */
+	FcPatternGetInteger (match, FC_INDEX, 0, &index);
+
+	tm->default_font = ltk_get_font(tm, file);
+
+	FcPatternDestroy (match);
+}
+
+LtkFont *
+ltk_create_font(char *path, uint16_t id)
+{
+	long len;
+	LtkFont *font = malloc(sizeof(LtkFont));
+	if (!font) {
+		(void)fprintf(stderr, "Out of memory!\n");
+		exit(1);
+	}
+	char *contents = ltk_read_file(path, &len);
+	if (!stbtt_InitFont(&font->info, contents, 0))
+	{
+		(void)fprintf(stderr, "Failed to load font %s\n", path);
+		exit(1);
+	}
+	/* FIXME: make use of the destroy function (last argument to hb_blob_create - see hb-blob.cc in harfbuzz source) */
+	hb_blob_t *blob = hb_blob_create(contents, len, HB_MEMORY_MODE_READONLY, NULL, NULL);
+	hb_face_t *face = hb_face_create(blob, 0);
+	/* FIXME: need to use destroy function in order for the original file data to be freed? */
+	hb_blob_destroy(blob);
+	font->hb = hb_font_create(face);
+	hb_face_destroy(face);
+	hb_ot_font_set_funcs(font->hb);
+	font->id = id;
+	font->refs = 0;
+
+	return font;
+}
+
+void
+ltk_destroy_font(LtkFont *font)
+{
+	free(font->info.data);
+	hb_font_destroy(font->hb);
+	free(font);
+}
+
+uint16_t
+ltk_load_font(LtkTextManager *tm, char *path)
+{
+	LtkFont *font = ltk_create_font(path, tm->font_id_cur++);
+	int ret;
+	khint_t k;
+	/* FIXME: does kh_destroy also free these copied strings properly? */
+	char *key = strdup(path);
+	k = kh_put(fontid, tm->font_paths, key, &ret);
+	kh_value(tm->font_paths, k) = font->id;
+	k = kh_put(fontstruct, tm->font_cache, (khint_t) font->id, &ret);
+	kh_value(tm->font_cache, k) = font;
+	k = kh_get(fontid, tm->font_paths, path);
+
+	return font->id;
+}
+
+uint16_t
+ltk_get_font(LtkTextManager *tm, char *path)
+{
+	int ret;
+	khint_t k;
+	uint16_t id;
+	k = kh_get(fontid, tm->font_paths, path);
+	if (k == kh_end(tm->font_paths)) {
+		id = ltk_load_font(tm, path);
+	} else {
+		id = kh_value(tm->font_paths, k);
+	}
+
+	return id;
+}
+
+/* FIXME: allow to either use fribidi for basic shaping and don't use harfbuzz then,
+          or just use harfbuzz (then fribidi doesn't need to do any shaping) */
+LtkTextLine *
+ltk_create_text_line(LtkTextManager *tm, char *text, uint16_t fontid, uint16_t size)
+{
+	/* NOTE: This doesn't actually take fontid into account right now - should it? */
+	LtkTextLine *tl = malloc(sizeof(LtkTextLine));
+	tl->start_segment = NULL;
+	LtkTextSegment *cur_ts = NULL;
+	LtkTextSegment *new_ts = NULL;
+	uint16_t cur_font_id = fontid;
+	int k;
+	LtkFont *font;
+
+	unsigned int ulen = u8_strlen(text);
+	FriBidiChar *log_str = malloc(sizeof(FriBidiChar) * ulen);
+	size_t inc = 0;
+	for (int i = 0; i < ulen; i++) {
+		log_str[i] = u8_nextmemchar(text, &inc);
+	}
+        FriBidiCharType *pbase_dir = malloc(sizeof(FriBidiCharType) * ulen);
+        for (int i = 0; i < ulen; i++) {
+                pbase_dir[i] = FRIBIDI_TYPE_ON;
+        }
+	FriBidiChar *vis_str = malloc(sizeof(FriBidiChar) * ulen);
+	ulen = fribidi_charset_to_unicode(FRIBIDI_CHAR_SET_UTF8, text, strlen(text), log_str);
+	fribidi_log2vis(log_str, ulen, pbase_dir, vis_str, NULL, NULL, NULL);
+
+	hb_unicode_funcs_t *ufuncs = hb_unicode_funcs_get_default();
+	hb_script_t cur_script = hb_unicode_script(ufuncs, vis_str[0]);
+	hb_script_t last_script = cur_script;
+	size_t pos = 0;
+	size_t last_pos = 0;
+	size_t start_pos = 0;
+	uint32_t ch;
+
+	for (int p = 0; p <= ulen; p++) {
+		cur_script = hb_unicode_script(ufuncs, vis_str[p]);
+		if (p == ulen ||
+			(last_script != cur_script &&
+			 cur_script != HB_SCRIPT_INHERITED &&
+			 cur_script != HB_SCRIPT_COMMON)) {
+			FcPattern *pat = FcPatternDuplicate(tm->fcpattern);
+			FcPattern *match;
+			FcResult result;
+			FcPatternAddBool(pat, FC_SCALABLE, 1);
+			FcConfigSubstitute(NULL, pat, FcMatchPattern);
+			FcDefaultSubstitute(pat);
+			FcCharSet *cs = FcCharSetCreate();
+			for (int i = start_pos; i < p; i++) {
+				FcCharSetAddChar(cs, vis_str[i]);
+			}
+			FcPatternAddCharSet(pat, FC_CHARSET, cs);
+			match = FcFontMatch(NULL, pat, &result);
+			char *file;
+			FcPatternGetString(match, FC_FILE, 0, &file);
+			cur_font_id = ltk_get_font(tm, file);
+			k = kh_get(fontstruct, tm->font_cache, cur_font_id);
+			font = kh_value(tm->font_cache, k);
+			FcPatternDestroy(match);
+			FcPatternDestroy(pat);
+			// handle case that this is the last character
+			if (p == ulen) {
+				last_script = cur_script;
+			}
+			/* FIXME: There should be better handling for cases
+			   where an error occurs while creating the segment */
+			new_ts = ltk_create_text_segment(
+				tm, vis_str + start_pos,
+				p - start_pos, cur_font_id,
+				size, last_script
+			);
+			if (!new_ts) continue;
+			new_ts->next = NULL;
+			if (!tl->start_segment) tl->start_segment = new_ts;
+			if (cur_ts) cur_ts->next = new_ts;
+			cur_ts = new_ts;
+
+			start_pos = p;
+			last_script = cur_script;
+		}
+	}
+
+	free(vis_str);
+	free(log_str);
+	free(pbase_dir);
+
+	/* calculate width of text line
+	   NOTE: doesn't work with mixed horizontal and vertical text */
+	LtkTextSegment *ts = tl->start_segment;
+	int is_hor = HB_DIRECTION_IS_HORIZONTAL(ts->dir);
+	tl->y_max = tl->x_max = INT_MIN;
+	tl->y_min = tl->x_min = INT_MAX;
+	tl->w = tl->h = 0;
+	while (ts) {
+		if (HB_DIRECTION_IS_HORIZONTAL(ts->dir) != is_hor) {
+			(void)fprintf(stderr, "WARNING: mixed horizontal/vertical text is not supported; ignoring\n");
+			continue;
+		}
+		if (is_hor) {
+			if (tl->y_max < ts->y_max) {
+				tl->y_max = ts->y_max;
+			}
+			if (tl->y_min > ts->y_min) {
+				tl->y_min = ts->y_min;
+			}
+			tl->w += ts->w;
+		} else {
+			if (tl->x_max < ts->x_max) {
+				tl->x_max = ts->x_max;
+			}
+			if (tl->x_min > ts->x_min) {
+				tl->x_min = ts->x_min;
+			}
+			tl->h += ts->h;
+		}
+		ts = ts->next;
+	}
+	if (is_hor) {
+		tl->h = tl->y_max - tl->y_min;
+	} else {
+		tl->w = tl->x_max - tl->x_min;
+	}
+
+	return tl;
+}
+
+void
+ltk_destroy_text_line(LtkTextLine *tl) {
+	LtkTextSegment *last_ts;
+	LtkTextSegment *cur_ts = tl->start_segment;
+	while (cur_ts) {
+		last_ts = cur_ts;
+		cur_ts = cur_ts->next;
+		ltk_destroy_text_segment(last_ts);
+	}
+}
+
+/* FIXME: could use unsigned int for fontid and size as long as there is code to check neither of them become too large
+   -> in case I want to get rid of uint_16_t, etc. */
+LtkTextSegment *
+ltk_create_text_segment(LtkTextManager *tm, uint32_t *text, unsigned int len, uint16_t fontid, uint16_t size, hb_script_t script)
+{
+	/* (x1*, y1*): top left corner (relative to origin and absolute)
+	   (x2*, y2*): bottom right corner (relative to origin and absolute) */
+	LtkFont *font;
+	khash_t(glyphinfo) *glyph_cache;
+	khint_t k;
+
+	k = kh_get(fontstruct, tm->font_cache, fontid);
+	font = kh_value(tm->font_cache, k);
+
+	uint32_t attr = fontid << 16 + size;
+	/* FIXME: turn this into ltk_get_glyph_cache */
+	k = kh_get(glyphcache, tm->glyph_cache, attr);
+	if (k == kh_end(tm->glyph_cache)) {
+		k = ltk_create_glyph_cache(tm, fontid, size);
+	}
+	glyph_cache = kh_value(tm->glyph_cache, k);
+
+	LtkTextSegment *ts = malloc(sizeof(LtkTextSegment));
+	if (!ts) {
+		(void)fprintf(stderr, "Out of memory!\n");
+		exit(1);
+	}
+	ts->str = malloc(sizeof(uint32_t) * (len + 1));
+	memcpy(ts->str, text, len * sizeof(uint32_t));
+	ts->str[len] = '\0';
+	ts->font_id = fontid;
+	ts->font_size = size;
+
+	hb_buffer_t *buf;
+	hb_glyph_info_t *ginf, *gi;
+	hb_glyph_position_t *gpos, *gp;
+	unsigned int text_len = 0;
+	if (len < 1) {
+		(void)printf("WARNING: ltk_render_text_segment: length of text is less than 1.\n");
+		return NULL;
+	}
+
+	buf = hb_buffer_create();
+	hb_direction_t dir = hb_script_get_horizontal_direction(script);
+	hb_buffer_set_direction(buf, dir);
+	hb_buffer_set_script(buf, script);
+	hb_buffer_add_codepoints(buf, ts->str, len, 0, len);
+	/* According to https://harfbuzz.github.io/the-distinction-between-levels-0-and-1.html
+	 * this should be level 1 clustering instead of level 0 */
+	hb_buffer_set_cluster_level(buf, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
+	hb_shape(font->hb, buf, NULL, 0);
+	ts->dir = hb_buffer_get_direction(buf);
+	ginf = hb_buffer_get_glyph_infos(buf, &text_len);
+	gpos = hb_buffer_get_glyph_positions(buf, &text_len);
+	float scale = stbtt_ScaleForMappingEmToPixels(&font->info, size);
+	LtkGlyph *last_glyph = NULL;
+
+	int x_min = INT_MAX, x_max = INT_MIN, y_min = INT_MAX, y_max = INT_MIN;
+	int x_abs = 0, y_abs = 0, x1_abs, y1_abs, x2_abs, y2_abs;
+	/* magic, do not touch */
+	LtkGlyph *glyph;
+	for (int i = 0; i < text_len; i++) {
+		gi = &ginf[i];
+		gp = &gpos[i];
+		glyph = malloc(sizeof(LtkGlyph));
+		glyph->info = ltk_get_glyph_info(font, gi->codepoint, scale, glyph_cache);
+		glyph->info->refs++;
+		/* FIXME: round instead of just casting */
+		glyph->x_offset = (int)(gp->x_offset * scale);
+		glyph->y_offset = (int)(gp->y_offset * scale);
+		glyph->x_advance = (int)(gp->x_advance * scale);
+		glyph->y_advance = (int)(gp->y_advance * scale);
+		glyph->next = NULL;
+		if (i == 0) {
+			ts->start_glyph = glyph;
+		} else {
+			last_glyph->next = glyph;
+		}
+		last_glyph = glyph;
+
+		/* Calculate position in order to determine full size of text segment */
+		x1_abs = x_abs + glyph->info->xoff + glyph->x_offset;
+		y1_abs = y_abs + glyph->info->yoff - glyph->y_offset;
+		/* Okay, wait, so should I check if the script is horizontal, and then add
+		   x_advance instead of glyph->info->w? It seems that the glyph width is
+		   usually smaller than x_advance, and spaces etc. are completely lost
+		   because their glyph width is 0. I have to distinguish between horizontal
+		   and vertical scripts, though because to calculate the maximum y position
+		   for horizontal scripts, I still need to use the glyph height since
+		   y_advance doesn't really do much there. I dunno, at least *something*
+		   works now... */
+		/* FIXME: THIS PROBABLY DOESN'T REALLY WORK */
+		if (HB_DIRECTION_IS_HORIZONTAL(dir)) {
+			x2_abs = x1_abs + glyph->x_advance;
+			y2_abs = y1_abs + glyph->info->h;
+		} else {
+			x2_abs = x1_abs + glyph->info->w;
+			y2_abs = y1_abs - glyph->y_advance;
+		}
+		glyph->x_abs = x1_abs;
+		glyph->y_abs = y1_abs;
+		if (x1_abs < x_min) x_min = x1_abs;
+		if (y1_abs < y_min) y_min = y1_abs;
+		if (x2_abs > x_max) x_max = x2_abs;
+		if (y2_abs > y_max) y_max = y2_abs;
+		x_abs += glyph->x_advance;
+		y_abs -= glyph->y_advance;
+	}
+        ts->start_x = -x_min;
+        ts->start_y = -y_min;
+	ts->w = x_max - x_min;
+	ts->h = y_max - y_min;
+	ts->x_min = x_min;
+	ts->y_min = y_min;
+	ts->x_max = x_max;
+	ts->y_max = y_max;
+
+	font->refs++;
+
+	return ts;
+}
+
+void
+ltk_destroy_glyph(LtkGlyph *glyph, khash_t(glyphinfo) *cache)
+{
+	int k;
+	if (--glyph->info->refs < 1) {
+		k = kh_get(glyphinfo, cache, glyph->info->id);
+		kh_del(glyphinfo, cache, k);
+		ltk_destroy_glyph_info(glyph->info);
+	}
+	free(glyph);
+}
+
+void
+ltk_destroy_text_segment(LtkTextSegment *ts)
+{
+	LtkGlyph *glyph, *next_glyph;
+	khash_t(glyphinfo) *gcache;
+	LtkFont *font;
+	int k;
+	glyph = ts->start_glyph;
+	k = kh_get(glyphinfo, ltk_global->tm->glyph_cache, ts->font_id << 16 + ts->font_size);
+	gcache = kh_value(ltk_global->tm->glyph_cache, k);
+	do {
+		next_glyph = glyph->next;
+		ltk_destroy_glyph(glyph, gcache);
+	} while (glyph = next_glyph);
+	k = kh_get(fontstruct, ltk_global->tm->font_cache, ts->font_id);
+	font = kh_value(ltk_global->tm->font_cache, k);
+	if (--font->refs < 1) {
+		kh_del(fontstruct, ltk_global->tm->font_cache, k);
+		ltk_destroy_font(font);
+	}
+	free(ts->str);
+	free(ts);
+}
+
+/* based on http://codemadness.org/git/dwm-font/file/drw.c.html#l315 */
+XImage *
+ltk_render_text_line(
+	LtkTextLine *tl,
+	Display *dpy,
+	Window window,
+	GC gc,
+	Colormap colormap,
+	XColor fg,
+	XColor bg)
+{
+	XWindowAttributes attrs;
+	XGetWindowAttributes(dpy, window, &attrs);
+	int depth = attrs.depth;
+	XImage *img = XCreateImage(dpy, CopyFromParent, depth, ZPixmap, 0, NULL, tl->w, tl->h, 32, 0);
+	img->data = calloc(img->bytes_per_line, img->height);
+	XInitImage(img);
+	int b;
+	for (int i = 0; i < tl->h; i++) {
+		b = img->bytes_per_line * i;
+		for (int j = 0; j < tl->w; j++) {
+			img->data[b++] = bg.blue / 257;
+			img->data[b++] = bg.green / 257;
+			img->data[b++] = bg.red / 257;
+			b++;
+		}
+	}
+
+	LtkTextSegment *ts = tl->start_segment;
+	int x = 0;
+	int y = 0;
+	int is_hor = HB_DIRECTION_IS_HORIZONTAL(ts->dir);
+	do {
+		if (is_hor) {
+			y = tl->h - tl->y_max;
+			ltk_render_text_segment(ts, x + ts->start_x, y, img, fg);
+			x += ts->w;
+		} else {
+			x = tl->w - tl->x_max;
+			ltk_render_text_segment(ts, x, y + ts->start_y, img, fg);
+			y += ts->h;
+		}
+	} while (ts = ts->next);
+
+	return img;
+}
+
+void
+ltk_render_text_segment(
+	LtkTextSegment *ts,
+	unsigned int start_x,
+	unsigned int start_y,
+	XImage *img,
+	XColor fg)
+{
+	LtkGlyph *glyph = ts->start_glyph;
+	int x_cur = start_x;
+	int y_cur = start_y;
+	int x, y;
+	double a;
+	int b;
+	do {
+		x = x_cur + glyph->info->xoff + glyph->x_offset;
+		y = y_cur + glyph->info->yoff - glyph->y_offset;
+		for (int i = 0; i < glyph->info->h; i++) {
+			for (int j = 0; j < glyph->info->w; j++) {
+				b = (y + i) * img->bytes_per_line + (x + j) * 4;
+				a = glyph->info->alphamap[i * glyph->info->w + j] / 255.0;
+				img->data[b] = (fg.blue * a + (1 - a) * (uint16_t)img->data[b] * 257) / 257;
+				img->data[b + 1] = (fg.green * a + (1 - a) * (uint16_t)img->data[b + 1] * 257) / 257;
+				img->data[b + 2] = (fg.red * a + (1 - a) * (uint16_t)img->data[b + 2] * 257) / 257;
+			}
+		}
+		x_cur += glyph->x_advance;
+		y_cur -= glyph->y_advance;
+	} while (glyph = glyph->next);
+}
+
+/*
+Notes: When inserting a character, check what the direction of the surrounding
+script is - if it is the same (or a weak direction), then just insert the char
+without re-doing the bidi algorithm. Only redo the whole line/paragraph is the
+dir of the inserted character is different. Assume the text is LTR until a strong
+character is inserted, i.e. the line should keep a flag if it already has a strong
+dir set.
+When reordering, the cursor needs to be kept in the right place:
+a) The logical to visual mapping from FriBidi needs to be used to find the position
+of the cursor in the text that gets passed to Harfbuzz.
+b) The cluster values from Harfbuzz need to be used to figure out where the cursor
+is on the screen.
+Harfbuzz also should be given some context - maybe even completely reshape the
+text until the last and next space? That would only be a problem with weird very
+long words (mainly nonsense). At least maybe take up to five or so chars on each
+side and pass even more with the optional context-passing feature for hb_shape.
+Question: Does both the logical and visual text need to be stored? The logical text
+is technically the master copy, but the visual text is what gets passed to harfbuzz.
+-> Actually, since the visual text has to be split into script runs anyways, maybe
+just append text to that (and also add it to the master buffer simultaneously). As
+soon as a different script is inserted, everything has to be redone anyways. Also,
+when reshaping with context, only the text in the current run has to be passed at all.
+*/
+
+struct ltk_gap_buffer *
+ltk_gap_buffer_create(void) {
+	struct ltk_gap_buffer *gb = malloc(sizeof(struct ltk_gap_buffer));
+	if (!gb)
+		goto error;
+	gb->buf = malloc(4 * sizeof(uint32_t));
+	if (!gb->buf)
+		goto error;
+	gb->buf_size = 8;
+	gb->gap_left = 0;
+	gb->gap_size = 8;
+	gb->gap_end_left = 8;
+	return gb;
+error:
+	(void)fprintf(stderr, "Out of memory while trying to allocate gap buffer\n");
+	exit(1);
+}
+
+void
+ltk_gap_buffer_resize_gap(struct ltk_gap_buffer *gb, int len) {
+	/* FIXME: Should this use realloc? It's usually more efficient, but
+	   in this case, I would still need to copy the part after the gap
+	   manually, so it could potentially be copied twice, which really
+	   wouldn't be good. Maybe use realloc if only a small part is after
+	   the gap and just regular malloc otherwise? */
+	int new_size = gb->buf_size - gb->gap-size + len;
+	struct ltk_gap_buffer *new = malloc(new_size * sizeof(uint32_t));
+	if (!new) {
+		(void)fprintf(stderr, "Out of memory while trying to resize gap buffer\n");
+		exit(1);
+	}
+	for (int i = 0; i < gb->gap_left; i++) {
+		new[i] = gb->buf[i];
+	}
+	for (int i = gb->gap_left + gb->gap_size; i < gb->gap_end_left) {
+		new[i - gb->gap_size + len] = gb->buf[i];
+	}
+	free(gb->buf);
+	gb->buf = new;
+}
+
+void
+ltk_gap_buffer_insert(struct ltk_gap_buffer *gb, uint32_t *new, size_t start, size_t len) {
+	if (gb->gap_size < len)
+		ltk_gap_buffer_resize_gap(gb, len + 8);
+	for (int i = 0; i < len; i++) {
+		gb->buf[gb->gap_left + i] = new[start + i];
+	}
+	gb->gap_left = gb->gap_left + len;
+	gb->gap_size -= len;
+}
+
+void
+ltk_gap_buffer_insert_single(struct ltk_gap_buffer *gb, uint32_t new) {
+	ltk_gap_buffer_insert(gb, &new, 0, 1);
+}
+
+void
+ltk_gap_buffer_move_gap(struct ltk_gap_buffer *gb, size_t pos) {
+	if (pos == gb->gap_left)
+		return;
+	if (pos < 0 || pos >= gb->gap_end_left - gb->gap_size) {
+		(void)fprintf(stderr, "Index out of range while moving gap buffer gap\n");
+		return;
+	}
+	if (pos >= gb->gap_left) {
+		for (int i = gb->gap_left; i < pos) {
+			gb->buf[i] = gb->buf[i + gb->gap_size];
+		}
+	} else {
+		for (int i = gb->gap_left - 1; i >= pos; i--) {
+			gb->buf[i + gb->gap_size] = gb->buf[i];
+		}
+	}
+	gb->gap_left = pos;
+}
+
+void
+ltk_gap_buffer_destroy(struct ltk_gap_buffer *gb) {
+	free(gb->buf);
+	free(gb);
+}
diff --git a/textedit_wip.h b/textedit_wip.h
@@ -0,0 +1,175 @@
+/*
+ * This file is part of the Lumidify ToolKit (LTK)
+ * Copyright (c) 2017, 2018, 2020 lumidify <nobody@lumidify.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _TEXT_HB_H_
+#define _TEXT_HB_H_
+
+/*
+Requires the following includes:
+<X11/Xlib.h>, <X11/Xutil.h>, "stb_truetype.h",
+"khash.h", <harfbuzz/hb.h>, <fribidi.h>,
+<fontconfig/fontconfig.h>
+*/
+
+/* Contains glyph info specific to one run of text */
+typedef struct ltk_glyph {
+	LtkGlyphInfo *info;
+	int x_offset; /* additional x offset given by harfbuzz */
+	int y_offset; /* additional y offset given by harfbuzz */
+	int x_advance;
+	int y_advance;
+	int x_abs;
+	int y_abs;
+	uint32_t cluster; /* index of char in original text - from harfbuzz */
+};
+
+struct ltk_gap_buffer {
+	uint32_t *buf;
+	size_t buf_size;
+	size_t gap_left;
+	size_t gap_size;
+	size_t gap_end_left;
+};
+
+struct ltk_text_buffer {
+	uint32_t *buffer;
+	struct ltk_glyph *glyphs;
+	size_t buf_size;
+	size_t buf_left;
+	size_t buf_gap_size;
+	size_t glyphs_size;
+	size_t glyphs_left;
+	size_t glyphs_gap_size;
+};
+
+typedef struct {
+	stbtt_fontinfo info;
+	hb_font_t *hb;
+	uint16_t id;
+	unsigned int refs;
+} LtkFont;
+
+/* Contains general info on glyphs that doesn't change regardless of the context */
+typedef struct _LtkGlyphInfo {
+	unsigned int id;
+	unsigned char *alphamap;
+	unsigned int w;
+	unsigned int h;
+	unsigned int xoff; /* x offset from origin to top left corner of glyph */
+	unsigned int yoff; /* y offset from origin to top left corner of glyph */
+	unsigned int refs;
+	/* FIXME: does refs need to be long? It could cause problems if a
+	program tries to cache/"keep alive" a lot of pages of text. */
+} LtkGlyphInfo;
+
+/* Single segment of text with same font */
+typedef struct LtkTextSegment {
+	uint16_t font_id;
+	uint16_t font_size;
+	unsigned int w;
+	unsigned int h;
+	int start_x;
+	int start_y;
+	int x_min;
+	int y_min;
+	int x_max;
+	int y_max;
+	hb_direction_t dir;
+	uint32_t *str;
+	LtkGlyph *start_glyph;
+	struct LtkTextSegment *next;
+} LtkTextSegment;
+
+/* Single line of text */
+typedef struct {
+	unsigned int w;
+	unsigned int h;
+	int x_max;
+	int x_min;
+	int y_max;
+	int y_min;
+	FriBidiParType dir;
+	LtkTextSegment *start_segment;
+} LtkTextLine;
+
+/* Hash definitions */
+/* glyph id -> glyph info struct */
+KHASH_MAP_INIT_INT(glyphinfo, LtkGlyphInfo*)
+/* font path, size -> glyph cache hash */
+KHASH_MAP_INIT_INT(glyphcache, khash_t(glyphinfo)*)
+/* font path -> font id */
+KHASH_MAP_INIT_STR(fontid, uint16_t)
+/* font id -> font struct */
+KHASH_MAP_INIT_INT(fontstruct, LtkFont*)
+
+typedef struct LtkTextManager {
+	khash_t(fontid) *font_paths;
+	khash_t(fontstruct) *font_cache;
+	khash_t(glyphcache) *glyph_cache;
+	FcPattern *fcpattern;
+	uint16_t default_font;
+	uint16_t font_id_cur;
+} LtkTextManager;
+
+LtkTextManager *ltk_init_text(char *font_name);
+
+void ltk_destroy_text_manager(LtkTextManager *tm);
+
+LtkGlyphInfo *ltk_create_glyph_info(LtkFont *font, unsigned int id, float scale);
+
+void ltk_destroy_glyph_info(LtkGlyphInfo *gi);
+
+LtkGlyphInfo *ltk_get_glyph_info(LtkFont *font, unsigned int id, float scale, khash_t(glyphinfo) *cache);
+
+khint_t ltk_create_glyph_cache(LtkTextManager *tm, uint16_t font_id, uint16_t font_size);
+
+void ltk_destroy_glyph_cache(khash_t(glyphinfo) *cache);
+
+void ltk_load_default_font(LtkTextManager *tm, char *name);
+
+LtkFont *ltk_create_font(char *path, uint16_t id);
+
+void ltk_destroy_font(LtkFont *font);
+
+/* FIXME: need to figure out how exactly the whole font system is going to work, especially with default fonts, etc. */
+uint16_t ltk_load_font(LtkTextManager *tm, char *path);
+
+uint16_t ltk_get_font(LtkTextManager *tm, char *path);
+
+/* TODO: different sizes, colors, styles, etc. */
+LtkTextLine *ltk_create_text_line(LtkTextManager *tm, char *text, uint16_t fontid, uint16_t size);
+
+/* FIXME: could use unsigned int for fontid and size as long as there is code to check neither of them become too large
+   -> in case I want to get rid of uint_16_t, etc. */
+LtkTextSegment *ltk_create_text_segment(LtkTextManager *tm, uint32_t *text, unsigned int text_len, uint16_t fontid, uint16_t size, hb_script_t script);
+
+void ltk_destroy_glyph(LtkGlyph *glyph, khash_t(glyphinfo) *cache);
+
+void ltk_destroy_text_segment(LtkTextSegment *ts);
+
+XImage *ltk_render_text_line(LtkTextLine *tl, Display *dpy, Window window, GC gc, Colormap colormap, XColor fg, XColor bg);
+
+void ltk_render_text_segment(LtkTextSegment *ts, unsigned int start_x, unsigned int start_y, XImage *img, XColor fg);
+
+
+#endif