expo: Support object alignment

Add support for left, right and centred alignment for text, in the
horizontal dimension.

Also support top, bottom and centred in the vertical dimension, for the
text object as a whole.

Alignment is not yet implemented for images. It has no meaning for
menus. A textline object uses a text object internally, so alignment
is supported there.

Provide some documentation to explain how objects are positioned.

Signed-off-by: Simon Glass <[email protected]>

1 files changed, 63 insertions, 0 deletions

diff --git a/include/expo.h b/include/expo.h
index 8833dcceb7e..001f7db2553 100644
--- a/include/expo.h
+++ b/include/expo.h
@@ -211,6 +211,19 @@ struct scene_obj_bbox {
 };
 
 /**
+ * struct scene_obj_offset - Offsets for drawing the object
+ *
+ * Stores the offset from x0, x1 at which objects are drawn
+ *
+ * @xofs: x offset
+ * @yofs: y offset
+ */
+struct scene_obj_offset {
+	int xofs;
+	int yofs;
+};
+
+/**
  * struct scene_obj_dims - Dimensions of the object being drawn
  *
  * Image and text objects have a dimension which can change depending on what
@@ -226,6 +239,30 @@ struct scene_obj_dims {
 };
 
 /**
+ * enum scene_obj_halign - Horizontal alignment of objects
+ *
+ * Objects are normally drawn on the left size of their bounding box. This
+ * properly allows aligning on the right or having the object centred.
+ *
+ * @SCENEOA_LEFT: Left of object is aligned with its x coordinate
+ * @SCENEOA_RIGHT: Right of object is aligned with x + w
+ * @SCENEOA_CENTRE: Centre of object is aligned with centre of bounding box
+ * @SCENEOA_TOP: Left of object is aligned with its x coordinate
+ * @SCENEOA_BOTTOM: Right of object is aligned with x + w
+ *
+ * Note: It would be nice to make this a char type but Sphinx riddles:
+ * ./include/expo.h:258: error: Cannot parse enum!
+ * enum scene_obj_align : char {
+ */
+enum scene_obj_align {
+	SCENEOA_LEFT,
+	SCENEOA_RIGHT,
+	SCENEOA_CENTRE,
+	SCENEOA_TOP = SCENEOA_LEFT,
+	SCENEOA_BOTTOM = SCENEOA_RIGHT,
+};
+
+/**
  * enum scene_obj_flags_t - flags for objects
  *
  * @SCENEOF_HIDE: object should be hidden
@@ -255,7 +292,10 @@ enum {
  * @id: ID number of the object
  * @type: Type of this object
  * @bbox: Bounding box for this object
+ * @ofs: Offset from x0, y0 where the object is drawn
  * @dims: Dimensions of the text/image (may be smaller than bbox)
+ * @horiz: Horizonal alignment
+ * @vert: Vertical alignment
  * @flags: Flags for this object
  * @bit_length: Number of bits used for this object in CMOS RAM
  * @start_bit: Start bit to use for this object in CMOS RAM
@@ -267,7 +307,10 @@ struct scene_obj {
 	uint id;
 	enum scene_obj_t type;
 	struct scene_obj_bbox bbox;
+	struct scene_obj_offset ofs;
 	struct scene_obj_dims dims;
+	enum scene_obj_align horiz;
+	enum scene_obj_align vert;
 	u8 flags;
 	u8 bit_length;
 	u16 start_bit;
@@ -756,6 +799,26 @@ int scene_obj_set_bbox(struct scene *scn, uint id, int x0, int y0, int x1,
 		       int y1);
 
 /**
+ * scene_obj_set_halign() - Set the horizontal alignment of an object
+ *
+ * @scn: Scene to update
+ * @id: ID of object to update
+ * @aln: Horizontal alignment to use
+ * Returns: 0 if OK, -ENOENT if @id is invalid
+ */
+int scene_obj_set_halign(struct scene *scn, uint id, enum scene_obj_align aln);
+
+/**
+ * scene_obj_set_valign() - Set the vertical alignment of an object
+ *
+ * @scn: Scene to update
+ * @id: ID of object to update
+ * @aln: Vertical alignment to use
+ * Returns: 0 if OK, -ENOENT if @id is invalid
+ */
+int scene_obj_set_valign(struct scene *scn, uint id, enum scene_obj_align aln);
+
+/**
  * scene_obj_set_hide() - Set whether an object is hidden
  *
  * The update happens when the expo is next rendered.