4 files changed, 237 insertions, 1 deletions
diff --git a/src/libs/Makefile.am b/src/libs/Makefile.am
index 48fb649..e0895ce 100644
--- a/src/libs/Makefile.am
+++ b/src/libs/Makefile.am
@@ -1 +1 @@
-SUBDIRS = ascii grid ray
+SUBDIRS = ascii grid ray txt
diff --git a/src/libs/txt/Makefile.am b/src/libs/txt/Makefile.am
new file mode 100644
index 0000000..88aa79b
--- /dev/null
+++ b/src/libs/txt/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LIBRARIES = libtxt.a
+libtxt_a_SOURCES = txt.c txt.h
+libtxt_a_CPPFLAGS = -I@top_srcdir@/src -I@top_srcdir@/src/libs
diff --git a/src/libs/txt/txt.c b/src/libs/txt/txt.c
new file mode 100644
index 0000000..e42d8c2
--- /dev/null
+++ b/src/libs/txt/txt.c
@@ -0,0 +1,200 @@
+#include <assert.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+#include "fb.h"
+
+#include "ascii/ascii.h"
+#include "txt.h"
+
+
+struct txt_t {
+	int	len, width, height;
+	char	str[];
+};
+
+
+/* compute the rectangle dimensions of the string in rendered pixels */
+static void measure_str(const char *str, int *res_width, int *res_height)
+{
+	int	rows = 1, cols = 0, col = 0;
+	char	c;
+
+	assert(str);
+	assert(res_width);
+	assert(res_height);
+
+	while (c = *str) {
+		switch (c) {
+		case ' '...'~':
+			col++;
+			break;
+
+		case '\n':
+			if (col > cols)
+				cols = col;
+			col = 0;
+			rows++;
+			break;
+
+		default:
+			break;
+		}
+		str++;
+	}
+
+	*res_height = 1 + rows * (ASCII_HEIGHT + 1);
+	*res_width = 1 + cols * (ASCII_WIDTH + 1);
+}
+
+
+txt_t * txt_new(const char *str)
+{
+	txt_t	*txt;
+	int	len;
+
+	assert(str);
+
+	len = strlen(str);
+
+	txt = calloc(1, sizeof(txt_t) + len + 1);
+	if (!txt)
+		return NULL;
+
+	txt->len = len;
+	memcpy(txt->str, str, len);
+
+	measure_str(txt->str, &txt->width, &txt->height);
+
+	return txt;
+}
+
+
+txt_t * txt_newf(const char *fmt, ...)
+{
+	char	buf[1024] = {};	/* XXX: it's not expected there will be long strings */
+	va_list	ap;
+
+	assert(fmt);
+
+	va_start(ap, fmt);
+	vsnprintf(buf, sizeof(buf) - 1, fmt, ap);
+	va_end(ap);
+
+	return txt_new(buf);
+}
+
+
+txt_t * txt_free(txt_t *txt)
+{
+	free(txt);
+
+	return NULL;
+}
+
+
+/* Adjusts x and y according to alignment, width, and height.  Returning the adjusted x and y
+ * in res_x, res_y.
+ *
+ * res_x,res_y will be the coordinate of the upper left corner of the rect
+ * described by width,height when aligned relative to x,y according to the
+ * specified alignment.
+ *
+ * e.g. if an alignment of TXT_HALIGN_LEFT,TXT_VALIGN_TOP is supplied, x,y is returned verbatim
+ * in res_x,res_y.
+ * an alignment of TXT_HALIGN_CENTER,TXT_VALIGN_CENTER returns x-width/2 and y-width/2.
+ */
+static void justify(txt_align_t alignment, int x, int y, unsigned width, unsigned height, int *res_x, int *res_y)
+{
+	assert(res_x);
+	assert(res_y);
+
+	switch (alignment.horiz) {
+	case TXT_HALIGN_CENTER:
+		x -= width >> 1;
+		break;
+
+	case TXT_HALIGN_LEFT:
+		break;
+
+	case TXT_HALIGN_RIGHT:
+		x -= width;
+		break;
+
+	default:
+		assert(0);
+	}
+
+	switch (alignment.vert) {
+	case TXT_VALIGN_CENTER:
+		y -= height >> 1;
+		break;
+
+	case TXT_VALIGN_TOP:
+		break;
+
+	case TXT_VALIGN_BOTTOM:
+		y -= height;
+		break;
+
+	default:
+		assert(0);
+	}
+
+	*res_x = x;
+	*res_y = y;
+}
+
+
+static int overlaps(int x1, int y1, unsigned w1, unsigned h1, int x2, int y2, unsigned w2, unsigned h2)
+{
+	/* TODO */
+	return 1;
+}
+
+
+static inline void draw_char(fb_fragment_t *fragment, uint32_t color, int x, int y, char c)
+{
+	/* TODO: this could be optimized to skip characters with no overlap */
+	for (int i = 0; i < ASCII_HEIGHT; i++) {
+		for (int j = 0; j < ASCII_WIDTH; j++) {
+			if (ascii_chars[c][i * ASCII_WIDTH + j])
+				fb_fragment_put_pixel_checked(fragment, x + j, y + i, color);
+		}
+	}
+}
+
+
+void txt_render_fragment(txt_t *txt, fb_fragment_t *fragment, uint32_t color, int x, int y, txt_align_t alignment)
+{
+	int	jx, jy, col, row;
+	char	c, *str;
+
+	assert(txt);
+	assert(fragment);
+
+	justify(alignment, x, y, txt->width, txt->height, &jx, &jy);
+
+	if (!overlaps(jx, jy, txt->width, txt->height,
+		      fragment->x, fragment->y,
+		      fragment->width, fragment->height))
+		return;
+
+
+	for (col = 0, row = 0, str = txt->str; *str; str++) {
+		switch (*str) {
+		case ' '...'~':
+			draw_char(fragment, color, jx + 1 + col * (ASCII_WIDTH + 1), jy + 1 + row * (ASCII_HEIGHT + 1), *str);
+			col++;
+			break;
+
+		case '\n':
+			col = 0;
+			row++;
+			break;
+
+		default:
+			break;
+		}
+	}
+}
diff --git a/src/libs/txt/txt.h b/src/libs/txt/txt.h
new file mode 100644
index 0000000..8c68e30
--- /dev/null
+++ b/src/libs/txt/txt.h
@@ -0,0 +1,33 @@
+#ifndef _TXT_H
+#define _TXT_H
+
+#include <stdint.h>
+
+typedef struct fb_fragment_t fb_fragment_t;
+typedef struct txt_t txt_t;
+
+typedef enum txt_halign_t {
+	TXT_HALIGN_CENTER,
+	TXT_HALIGN_LEFT,
+	TXT_HALIGN_RIGHT,
+	TXT_HALIGN_CNT,
+} txt_halign_t;
+
+typedef enum txt_valign_t {
+	TXT_VALIGN_CENTER,
+	TXT_VALIGN_TOP,
+	TXT_VALIGN_BOTTOM,
+	TXT_VALIGN_CNT,
+} txt_valign_t;
+
+typedef struct txt_align_t {
+	txt_halign_t	horiz;
+	txt_valign_t	vert;
+} txt_align_t;
+
+txt_t * txt_new(const char *str);
+txt_t * txt_newf(const char *fmt, ...);
+txt_t * txt_free(txt_t *txt);
+void txt_render_fragment(txt_t *txt, fb_fragment_t *fragment, uint32_t color, int x, int y, txt_align_t alignment);
+
+#endif