console: Allow measuring the bounding box of text

For laying out text accurately it is necessary to know the width and
height of the text. Add a measure() method to the console API, so this
can be supported.

Add an implementation for truetype and a base implementation for the
normal console.

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

diff --git a/drivers/video/console_truetype.c b/drivers/video/console_truetype.c
index 6f3fc82f9b05682909b0ccba71df5e828f4e645c..288123a2e065a45c58a7057324a3916b6529b9f3 100644 (file)
--- a/drivers/video/console_truetype.c
+++ b/drivers/video/console_truetype.c
@@ -614,8 +614,8 @@ static void select_metrics(struct udevice *dev, struct console_tt_metrics *met)
        vc_priv->tab_width_frac = VID_TO_POS(met->font_size) * 8 / 2;
 }
 
-static int truetype_select_font(struct udevice *dev, const char *name,
-                               uint size)
+static int get_metrics(struct udevice *dev, const char *name, uint size,
+                      struct console_tt_metrics **metp)
 {
        struct console_tt_priv *priv = dev_get_priv(dev);
        struct console_tt_metrics *met;
@@ -653,11 +653,70 @@ static int truetype_select_font(struct udevice *dev, const char *name,
                met = priv->metrics;
        }
 
+       *metp = met;
+
+       return 0;
+}
+
+static int truetype_select_font(struct udevice *dev, const char *name,
+                               uint size)
+{
+       struct console_tt_metrics *met;
+       int ret;
+
+       ret = get_metrics(dev, name, size, &met);
+       if (ret)
+               return log_msg_ret("sel", ret);
+
        select_metrics(dev, met);
 
        return 0;
 }
 
+int truetype_measure(struct udevice *dev, const char *name, uint size,
+                    const char *text, struct vidconsole_bbox *bbox)
+{
+       struct console_tt_metrics *met;
+       stbtt_fontinfo *font;
+       int lsb, advance;
+       const char *s;
+       int width;
+       int last;
+       int ret;
+
+       ret = get_metrics(dev, name, size, &met);
+       if (ret)
+               return log_msg_ret("sel", ret);
+
+       bbox->valid = false;
+       if (!*text)
+               return 0;
+
+       font = &met->font;
+       width = 0;
+       for (last = 0, s = text; *s; s++) {
+               int ch = *s;
+
+               /* Used kerning to fine-tune the position of this character */
+               if (last)
+                       width += stbtt_GetCodepointKernAdvance(font, last, ch);
+
+               /* First get some basic metrics about this character */
+               stbtt_GetCodepointHMetrics(font, ch, &advance, &lsb);
+
+               width += advance;
+               last = ch;
+       }
+
+       bbox->valid = true;
+       bbox->x0 = 0;
+       bbox->y0 = 0;
+       bbox->x1 = tt_ceil((double)width * met->scale);
+       bbox->y1 = met->font_size;
+
+       return 0;
+}
+
 const char *console_truetype_get_font_size(struct udevice *dev, uint *sizep)
 {
        struct console_tt_priv *priv = dev_get_priv(dev);
@@ -709,6 +768,7 @@ struct vidconsole_ops console_truetype_ops = {
        .get_font       = console_truetype_get_font,
        .get_font_size  = console_truetype_get_font_size,
        .select_font    = truetype_select_font,
+       .measure        = truetype_measure,
 };
 
 U_BOOT_DRIVER(vidconsole_truetype) = {

diff --git a/drivers/video/vidconsole-uclass.c b/drivers/video/vidconsole-uclass.c
index 3f89537c47b76bcca66b7db71e0a9cdecd0dc636..05f9304780967648ee67b38695278bb59800b1b6 100644 (file)
--- a/drivers/video/vidconsole-uclass.c
+++ b/drivers/video/vidconsole-uclass.c
@@ -596,6 +596,28 @@ int vidconsole_select_font(struct udevice *dev, const char *name, uint size)
        return ops->select_font(dev, name, size);
 }
 
+int vidconsole_measure(struct udevice *dev, const char *name, uint size,
+                      const char *text, struct vidconsole_bbox *bbox)
+{
+       struct vidconsole_priv *priv = dev_get_uclass_priv(dev);
+       struct vidconsole_ops *ops = vidconsole_get_ops(dev);
+       int ret;
+
+       if (ops->select_font) {
+               ret = ops->measure(dev, name, size, text, bbox);
+               if (ret != -ENOSYS)
+                       return ret;
+       }
+
+       bbox->valid = true;
+       bbox->x0 = 0;
+       bbox->y0 = 0;
+       bbox->x1 = priv->x_charsize * strlen(text);
+       bbox->y1 = priv->y_charsize;
+
+       return 0;
+}
+
 void vidconsole_push_colour(struct udevice *dev, enum colour_idx fg,
                            enum colour_idx bg, struct vidconsole_colour *old)
 {

diff --git a/include/video_console.h b/include/video_console.h
index 81d4c4d874dff40db999ccdb7180945cec2e75cc..2694e44f6ecf395f1aa257229722a98353f9d8fd 100644 (file)
--- a/include/video_console.h
+++ b/include/video_console.h
@@ -82,6 +82,27 @@ struct vidconsole_colour {
        u32 colour_bg;
 };
 
+/**
+ * struct vidconsole_bbox - Bounding box of text
+ *
+ * This describes the bounding box of something, measured in pixels. The x0/y0
+ * pair is inclusive; the x1/y2 pair is exclusive, meaning that it is one pixel
+ * beyond the extent of the object
+ *
+ * @valid: Values are valid (bounding box is known)
+ * @x0: left x position, in pixels from left side
+ * @y0: top y position, in pixels from top
+ * @x1: right x position + 1
+ * @y1: botton y position + 1
+ */
+struct vidconsole_bbox {
+       bool valid;
+       int x0;
+       int y0;
+       int x1;
+       int y1;
+};
+
 /**
  * struct vidconsole_ops - Video console operations
  *
@@ -189,6 +210,20 @@ struct vidconsole_ops {
         * Returns: 0 on success, -ENOENT if no such font
         */
        int (*select_font)(struct udevice *dev, const char *name, uint size);
+
+       /**
+        * measure() - Measure the bounds of some text
+        *
+        * @dev:        Device to adjust
+        * @name:       Font name to use (NULL to use default)
+        * @size:       Font size to use (0 to use default)
+        * @text:       Text to measure
+        * @bbox:       Returns bounding box of text, assuming it is positioned
+        *              at 0,0
+        * Returns: 0 on success, -ENOENT if no such font
+        */
+       int (*measure)(struct udevice *dev, const char *name, uint size,
+                      const char *text, struct vidconsole_bbox *bbox);
 };
 
 /* Get a pointer to the driver operations for a video console device */
@@ -215,6 +250,19 @@ int vidconsole_get_font(struct udevice *dev, int seq,
  */
 int vidconsole_select_font(struct udevice *dev, const char *name, uint size);
 
+/*
+ * vidconsole_measure() - Measuring the bounding box of some text
+ *
+ * @dev: Console device to use
+ * @name: Font name, NULL for default
+ * @size: Font size, ignored if @name is NULL
+ * @text: Text to measure
+ * @bbox: Returns nounding box of text
+ * Returns: 0 if OK, -ve on error
+ */
+int vidconsole_measure(struct udevice *dev, const char *name, uint size,
+                      const char *text, struct vidconsole_bbox *bbox);
+
 /**
  * vidconsole_push_colour() - Temporarily change the font colour
  *