video: Refactor to allow more than one font size

At present the truetype console supports only a single font and size. It
is useful to be able to support different combinations. As a first step,
move the metrics into there own structure and allow having multiple
metrics.

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 113 insertions, 42 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 44ab9e708f..3293837665 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -176,6 +176,21 @@ config CONSOLE_TRUETYPE_SIZE
 	  method to select the display's physical size, which would allow
 	  U-Boot to calculate the correct font size.
 
+config CONSOLE_TRUETYPE_MAX_METRICS
+	int "TrueType maximum number of font / size combinations"
+	depends on CONSOLE_TRUETYPE
+	default 10 if EXPO
+	default 1
+	help
+	  This sets the number of font / size combinations which can be used by
+	  the console. For simple console use a single font is enough. When
+	  boot menus are in use, this may need to be increased.
+
+	  Note that a separate entry is needed for each font size, even if the
+	  font itself is the same. This is because the entry caches various
+	  font metrics which are expensive to regenerate each time the font
+	  size changes.
+
 config SYS_WHITE_ON_BLACK
 	bool "Display console as white on a black background"
 	default y if ARCH_AT91 || ARCH_EXYNOS || ARCH_ROCKCHIP || ARCH_TEGRA || X86 || ARCH_SUNXI
diff --git a/drivers/video/console_truetype.c b/drivers/video/console_truetype.c
index 1331ce8d89..ab7bcda197 100644
--- a/drivers/video/console_truetype.c
+++ b/drivers/video/console_truetype.c
@@ -94,17 +94,15 @@ struct pos_info {
 #define POS_HISTORY_SIZE	(CONFIG_SYS_CBSIZE * 11 / 10)
 
 /**
- * struct console_tt_priv - Private data for this driver
+ * struct console_tt_metrics - Information about a font / size combination
+ *
+ * This caches various font metrics which are expensive to regenerate each time
+ * the font size changes. There is one of these for each font / size combination
+ * that is being used
  *
  * @font_size:	Vertical font size in pixels
  * @font_data:	Pointer to TrueType font file contents
  * @font:	TrueType font information for the current font
- * @pos:	List of cursor positions for each character written. This is
- *		used to handle backspace. We clear the frame buffer between
- *		the last position and the current position, thus erasing the
- *		last character. We record enough characters to go back to the
- *		start of the current command line.
- * @pos_ptr:	Current position in the position history
  * @baseline:	Pixel offset of the font's baseline from the cursor position.
  *		This is the 'ascent' of the font, scaled to pixel coordinates.
  *		It measures the distance from the baseline to the top of the
@@ -113,25 +111,45 @@ struct pos_info {
  *		of the font. It is used by the STB library to generate images
  *		of the correct size.
  */
-struct console_tt_priv {
+struct console_tt_metrics {
 	int font_size;
-	u8 *font_data;
+	const u8 *font_data;
 	stbtt_fontinfo font;
-	struct pos_info pos[POS_HISTORY_SIZE];
-	int pos_ptr;
 	int baseline;
 	double scale;
 };
 
+/**
+ * struct console_tt_priv - Private data for this driver
+ *
+ * @cur_met:	Current metrics being used
+ * @metrics:	List metrics that can be used
+ * @num_metrics:	Number of available metrics
+ * @pos:	List of cursor positions for each character written. This is
+ *		used to handle backspace. We clear the frame buffer between
+ *		the last position and the current position, thus erasing the
+ *		last character. We record enough characters to go back to the
+ *		start of the current command line.
+ * @pos_ptr:	Current position in the position history
+ */
+struct console_tt_priv {
+	struct console_tt_metrics *cur_met;
+	struct console_tt_metrics metrics[CONFIG_CONSOLE_TRUETYPE_MAX_METRICS];
+	int num_metrics;
+	struct pos_info pos[POS_HISTORY_SIZE];
+	int pos_ptr;
+};
+
 static int console_truetype_set_row(struct udevice *dev, uint row, int clr)
 {
 	struct video_priv *vid_priv = dev_get_uclass_priv(dev->parent);
 	struct console_tt_priv *priv = dev_get_priv(dev);
+	struct console_tt_metrics *met = priv->cur_met;
 	void *end, *line;
 	int ret;
 
-	line = vid_priv->fb + row * priv->font_size * vid_priv->line_length;
-	end = line + priv->font_size * vid_priv->line_length;
+	line = vid_priv->fb + row * met->font_size * vid_priv->line_length;
+	end = line + met->font_size * vid_priv->line_length;
 
 	switch (vid_priv->bpix) {
 #ifdef CONFIG_VIDEO_BPP8
@@ -176,19 +194,20 @@ static int console_truetype_move_rows(struct udevice *dev, uint rowdst,
 {
 	struct video_priv *vid_priv = dev_get_uclass_priv(dev->parent);
 	struct console_tt_priv *priv = dev_get_priv(dev);
+	struct console_tt_metrics *met = priv->cur_met;
 	void *dst;
 	void *src;
 	int i, diff, ret;
 
-	dst = vid_priv->fb + rowdst * priv->font_size * vid_priv->line_length;
-	src = vid_priv->fb + rowsrc * priv->font_size * vid_priv->line_length;
-	ret = vidconsole_memmove(dev, dst, src, priv->font_size *
+	dst = vid_priv->fb + rowdst * met->font_size * vid_priv->line_length;
+	src = vid_priv->fb + rowsrc * met->font_size * vid_priv->line_length;
+	ret = vidconsole_memmove(dev, dst, src, met->font_size *
 				 vid_priv->line_length * count);
 	if (ret)
 		return ret;
 
 	/* Scroll up our position history */
-	diff = (rowsrc - rowdst) * priv->font_size;
+	diff = (rowsrc - rowdst) * met->font_size;
 	for (i = 0; i < priv->pos_ptr; i++)
 		priv->pos[i].ypos -= diff;
 
@@ -202,7 +221,8 @@ static int console_truetype_putc_xy(struct udevice *dev, uint x, uint y,
 	struct udevice *vid = dev->parent;
 	struct video_priv *vid_priv = dev_get_uclass_priv(vid);
 	struct console_tt_priv *priv = dev_get_priv(dev);
-	stbtt_fontinfo *font = &priv->font;
+	struct console_tt_metrics *met = priv->cur_met;
+	stbtt_fontinfo *font = &met->font;
 	int width, height, xoff, yoff;
 	double xpos, x_shift;
 	int lsb;
@@ -222,7 +242,7 @@ static int console_truetype_putc_xy(struct udevice *dev, uint x, uint y,
 	 * this character */
 	xpos = frac(VID_TO_PIXEL((double)x));
 	if (vc_priv->last_ch) {
-		xpos += priv->scale * stbtt_GetCodepointKernAdvance(font,
+		xpos += met->scale * stbtt_GetCodepointKernAdvance(font,
 							vc_priv->last_ch, ch);
 	}
 
@@ -233,7 +253,7 @@ static int console_truetype_putc_xy(struct udevice *dev, uint x, uint y,
 	 * it dictates how much the cursor will move forward on the line.
 	 */
 	x_shift = xpos - (double)tt_floor(xpos);
-	xpos += advance * priv->scale;
+	xpos += advance * met->scale;
 	width_frac = (int)VID_TO_POS(xpos);
 	if (x + width_frac >= vc_priv->xsize_frac)
 		return -EAGAIN;
@@ -252,7 +272,7 @@ static int console_truetype_putc_xy(struct udevice *dev, uint x, uint y,
 	 * image of the character. For empty characters, like ' ', data will
 	 * return NULL;
 	 */
-	data = stbtt_GetCodepointBitmapSubpixel(font, priv->scale, priv->scale,
+	data = stbtt_GetCodepointBitmapSubpixel(font, met->scale, met->scale,
 						x_shift, 0, ch, &width, &height,
 						&xoff, &yoff);
 	if (!data)
@@ -262,7 +282,7 @@ static int console_truetype_putc_xy(struct udevice *dev, uint x, uint y,
 	bits = data;
 	start = vid_priv->fb + y * vid_priv->line_length +
 		VID_TO_PIXEL(x) * VNBYTES(vid_priv->bpix);
-	linenum = priv->baseline + yoff;
+	linenum = met->baseline + yoff;
 	if (linenum > 0)
 		start += linenum * vid_priv->line_length;
 	line = start;
@@ -562,42 +582,78 @@ static u8 *console_truetype_find_font(void)
 	return NULL;
 }
 
+/**
+ * vidconsole_add_metrics() - Add a new font/size combination
+ *
+ * @dev:	Video console device to update
+ * @font_name:	Name of font
+ * @font_size:	Size of the font (norminal pixel height)
+ * @font_data:	Pointer to the font data
+ * @return 0 if OK, -EPERM if stbtt failed, -E2BIG if the the metrics table is
+ *	full
+ */
+static int vidconsole_add_metrics(struct udevice *dev, const void *font_data,
+				  uint font_size)
+{
+	struct console_tt_priv *priv = dev_get_priv(dev);
+	struct console_tt_metrics *met;
+	stbtt_fontinfo *font;
+	int ascent;
+
+	if (priv->num_metrics == CONFIG_CONSOLE_TRUETYPE_MAX_METRICS)
+		return log_msg_ret("num", -E2BIG);
+
+	met = &priv->metrics[priv->num_metrics];
+	met->font_size = font_size;
+	met->font_data = font_data;
+
+	font = &met->font;
+	if (!stbtt_InitFont(font, font_data, 0)) {
+		debug("%s: Font init failed\n", __func__);
+		return -EPERM;
+	}
+
+	/* Pre-calculate some things we will need regularly */
+	met->scale = stbtt_ScaleForPixelHeight(font, font_size);
+	stbtt_GetFontVMetrics(font, &ascent, 0, 0);
+	met->baseline = (int)(ascent * met->scale);
+
+	return priv->num_metrics++;
+}
+
 static int console_truetype_probe(struct udevice *dev)
 {
 	struct vidconsole_priv *vc_priv = dev_get_uclass_priv(dev);
 	struct console_tt_priv *priv = dev_get_priv(dev);
 	struct udevice *vid_dev = dev->parent;
 	struct video_priv *vid_priv = dev_get_uclass_priv(vid_dev);
-	stbtt_fontinfo *font = &priv->font;
-	int ascent;
+	void *font_data;
+	uint font_size;
+	int ret;
 
 	debug("%s: start\n", __func__);
 	if (vid_priv->font_size)
-		priv->font_size = vid_priv->font_size;
+		font_size = vid_priv->font_size;
 	else
-		priv->font_size = CONFIG_CONSOLE_TRUETYPE_SIZE;
-	priv->font_data = console_truetype_find_font();
-	if (!priv->font_data) {
+		font_size = CONFIG_CONSOLE_TRUETYPE_SIZE;
+	font_data = console_truetype_find_font();
+	if (!font_data) {
 		debug("%s: Could not find any fonts\n", __func__);
 		return -EBFONT;
 	}
 
-	vc_priv->x_charsize = priv->font_size;
-	vc_priv->y_charsize = priv->font_size;
-	vc_priv->xstart_frac = VID_TO_POS(2);
-	vc_priv->cols = vid_priv->xsize / priv->font_size;
-	vc_priv->rows = vid_priv->ysize / priv->font_size;
-	vc_priv->tab_width_frac = VID_TO_POS(priv->font_size) * 8 / 2;
+	ret = vidconsole_add_metrics(dev, font_data, font_size);
+	if (ret < 0)
+		return log_msg_ret("add", ret);
+	priv->cur_met = &priv->metrics[ret];
 
-	if (!stbtt_InitFont(font, priv->font_data, 0)) {
-		debug("%s: Font init failed\n", __func__);
-		return -EPERM;
-	}
+	vc_priv->x_charsize = font_size;
+	vc_priv->y_charsize = font_size;
+	vc_priv->xstart_frac = VID_TO_POS(2);
+	vc_priv->cols = vid_priv->xsize / font_size;
+	vc_priv->rows = vid_priv->ysize / font_size;
+	vc_priv->tab_width_frac = VID_TO_POS(font_size) * 8 / 2;
 
-	/* Pre-calculate some things we will need regularly */
-	priv->scale = stbtt_ScaleForPixelHeight(font, priv->font_size);
-	stbtt_GetFontVMetrics(font, &ascent, 0, 0);
-	priv->baseline = (int)(ascent * priv->scale);
 	debug("%s: ready\n", __func__);
 
 	return 0;