[PATCH v2 3/8] video console: add support for fonts wider than 1 byte

[Dzmitry Sankouski]

Devices with high ppi may benefit from wider fonts.

Current width implementation is limited by 1 byte, i.e. 8 bits.
New version iterates VIDEO_FONT_BYTE_WIDTH times, to process all
width bytes, thus allowing fonts wider than 1 byte.

Signed-off-by: Dzmitry Sankouski <dsankouski at gmail.com>
---
Charges for v2:
- replace TAIL_BIT_COUNT macro with c code
- rename refactoring

 drivers/video/console_simple.c | 93 +++++++++++++++++++++-------------
 1 file changed, 59 insertions(+), 34 deletions(-)

diff --git a/drivers/video/console_simple.c b/drivers/video/console_simple.c
index 1eb47be449..cdc26cac30 100644
--- a/drivers/video/console_simple.c
+++ b/drivers/video/console_simple.c
@@ -13,6 +13,7 @@
 #include <video_font.h>		/* Get font data, width and height */
 
 #define VIDEO_FONT_BYTE_WIDTH	((VIDEO_FONT_WIDTH / 8) + (VIDEO_FONT_WIDTH % 8 > 0))
+#define VIDEO_FONT_CHAR_PIXEL_BYTES	(VIDEO_FONT_HEIGHT * VIDEO_FONT_BYTE_WIDTH)
 
 #define FLIPPED_DIRECTION 1
 #define NORMAL_DIRECTION 0
@@ -95,9 +96,9 @@ static inline void fill_pixel_and_goto_next(void **dstp, u32 value, int pbytes,
 static int fill_char_horizontally(uchar *pfont, void **line, struct video_priv *vid_priv,
 				  bool direction)
 {
-	int step, line_step, pbytes, ret;
+	int step, line_step, pbytes, bitcount = 8, width_remainder, ret;
 	void *dst;
-	u8 mask = 0x80;
+	u8 mask;
 
 	ret = check_bpix_support(vid_priv->bpix);
 	if (ret)
@@ -111,21 +112,32 @@ static int fill_char_horizontally(uchar *pfont, void **line, struct video_priv *
 		step = pbytes;
 		line_step = -vid_priv->line_length;
 	}
-	for (int col = 0; col < VIDEO_FONT_WIDTH; col++) {
-		dst = *line;
-		for (int row = 0; row < VIDEO_FONT_HEIGHT; row++) {
-			u32 value = (pfont[row * VIDEO_FONT_BYTE_WIDTH] & mask) ?
-						vid_priv->colour_fg :
-						vid_priv->colour_bg;
-
-			fill_pixel_and_goto_next(&dst,
-						 value,
-						 pbytes,
-						 step
-			);
+
+	width_remainder = VIDEO_FONT_WIDTH % 8;
+	for (int col = 0; col < VIDEO_FONT_BYTE_WIDTH; col++) {
+		mask = 0x80;
+		if (width_remainder) {
+			bool is_last_iteration = (VIDEO_FONT_BYTE_WIDTH - col == 1);
+
+			if (is_last_iteration)
+				bitcount = width_remainder;
+		}
+		for (int bit = 0; bit < bitcount; bit++) {
+			dst = *line;
+			for (int row = 0; row < VIDEO_FONT_HEIGHT; row++) {
+				u32 value = (pfont[row * VIDEO_FONT_BYTE_WIDTH] & mask) ?
+							vid_priv->colour_fg :
+							vid_priv->colour_bg;
+
+				fill_pixel_and_goto_next(&dst,
+							 value,
+							 pbytes,
+							 step
+				);
+			}
+			*line += line_step;
+			mask >>= 1;
 		}
-		*line += line_step;
-		mask >>= 1;
 	}
 	return ret;
 }
@@ -158,7 +170,7 @@ static int fill_char_horizontally(uchar *pfont, void **line, struct video_priv *
 static int fill_char_vertically(uchar *pfont, void **line, struct video_priv *vid_priv,
 				bool direction)
 {
-	int step, line_step, pbytes, ret;
+	int step, line_step, pbytes, bitcount, width_remainder, ret;
 	void *dst;
 
 	ret = check_bpix_support(vid_priv->bpix);
@@ -174,23 +186,36 @@ static int fill_char_vertically(uchar *pfont, void **line, struct video_priv *vi
 		line_step = vid_priv->line_length;
 	}
 
+	width_remainder = VIDEO_FONT_WIDTH % 8;
 	for (int row = 0; row < VIDEO_FONT_HEIGHT; row++) {
+		uchar bits;
+
+		bitcount = 8;
 		dst = *line;
-		uchar bits = pfont[row];
-
-		for (int i = 0; i < VIDEO_FONT_WIDTH; i++) {
-			u32 value = (bits & 0x80) ?
-				vid_priv->colour_fg :
-				vid_priv->colour_bg;
-
-			fill_pixel_and_goto_next(&dst,
-						 value,
-						 pbytes,
-						 step
-			);
-			bits <<= 1;
+		for (int col = 0; col < VIDEO_FONT_BYTE_WIDTH; col++) {
+			if (width_remainder) {
+				bool is_last_iteration = (VIDEO_FONT_BYTE_WIDTH - col == 1);
+
+				if (is_last_iteration)
+					bitcount = width_remainder;
+			}
+			bits = pfont[col];
+
+			for (int bit = 0; bit < bitcount; bit++) {
+				u32 value = (bits & 0x80) ?
+					vid_priv->colour_fg :
+					vid_priv->colour_bg;
+
+				fill_pixel_and_goto_next(&dst,
+							 value,
+							 pbytes,
+							 step
+				);
+				bits <<= 1;
+			}
 		}
 		*line += line_step;
+		pfont += VIDEO_FONT_BYTE_WIDTH;
 	}
 	return ret;
 }
@@ -249,7 +274,7 @@ static int console_putc_xy(struct udevice *dev, uint x_frac, uint y, char ch)
 	int pbytes = VNBYTES(vid_priv->bpix);
 	int x, linenum, ret;
 	void *start, *line;
-	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_HEIGHT;
+	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_CHAR_PIXEL_BYTES;
 
 	if (x_frac + VID_TO_POS(vc_priv->x_charsize) > vc_priv->xsize_frac)
 		return -EAGAIN;
@@ -358,7 +383,7 @@ static int console_putc_xy_1(struct udevice *dev, uint x_frac, uint y, char ch)
 	int pbytes = VNBYTES(vid_priv->bpix);
 	int x, linenum, ret;
 	void *start, *line;
-	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_HEIGHT;
+	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_CHAR_PIXEL_BYTES;
 
 	if (x_frac + VID_TO_POS(vc_priv->x_charsize) > vc_priv->xsize_frac)
 		return -EAGAIN;
@@ -429,7 +454,7 @@ static int console_putc_xy_2(struct udevice *dev, uint x_frac, uint y, char ch)
 	int pbytes = VNBYTES(vid_priv->bpix);
 	int linenum, x, ret;
 	void *start, *line;
-	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_HEIGHT;
+	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_CHAR_PIXEL_BYTES;
 
 	if (x_frac + VID_TO_POS(vc_priv->x_charsize) > vc_priv->xsize_frac)
 		return -EAGAIN;
@@ -504,7 +529,7 @@ static int console_putc_xy_3(struct udevice *dev, uint x_frac, uint y, char ch)
 	int pbytes = VNBYTES(vid_priv->bpix);
 	int linenum, x, ret;
 	void *start, *line;
-	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_HEIGHT;
+	uchar *pfont = video_fontdata + (u8)ch * VIDEO_FONT_CHAR_PIXEL_BYTES;
 
 	if (x_frac + VID_TO_POS(vc_priv->x_charsize) > vc_priv->xsize_frac)
 		return -EAGAIN;
-- 
2.30.2