gstreamer/ext/pango/gsttextoverlay.h

#ifndef __GST_TEXT_OVERLAY_H__
#define __GST_TEXT_OVERLAY_H__

#include <gst/gst.h>
#include <pango/pangoft2.h>

G_BEGIN_DECLS

#define GST_TYPE_TEXT_OVERLAY            (gst_text_overlay_get_type())
#define GST_TEXT_OVERLAY(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),\
                                         GST_TYPE_TEXT_OVERLAY, GstTextOverlay))
#define GST_TEXT_OVERLAY_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),\
                                         GST_TYPE_TEXT_OVERLAY,GstTextOverlayClass))
#define GST_TEXT_OVERLAY_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),\
                                         GST_TYPE_TEXT_OVERLAY, GstTextOverlayClass))
#define GST_IS_TEXT_OVERLAY(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),\
                                         GST_TYPE_TEXT_OVERLAY))
#define GST_IS_TEXT_OVERLAY_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),\
                                         GST_TYPE_TEXT_OVERLAY))

typedef struct _GstTextOverlay      GstTextOverlay;
typedef struct _GstTextOverlayClass GstTextOverlayClass;

/**
 * GstTextOverlayVAlign:
 * @GST_TEXT_OVERLAY_VALIGN_BASELINE: draw text on the baseline
 * @GST_TEXT_OVERLAY_VALIGN_BOTTOM: draw text on the bottom
 * @GST_TEXT_OVERLAY_VALIGN_TOP: draw test on top
 *
 * Vertical alignment of the text.
 */
typedef enum {
    GST_TEXT_OVERLAY_VALIGN_BASELINE,
    GST_TEXT_OVERLAY_VALIGN_BOTTOM,
    GST_TEXT_OVERLAY_VALIGN_TOP
} GstTextOverlayVAlign;

/**
 * GstTextOverlayHAlign:
 * @GST_TEXT_OVERLAY_HALIGN_LEFT: align text left
 * @GST_TEXT_OVERLAY_HALIGN_CENTER: align text center
 * @GST_TEXT_OVERLAY_HALIGN_RIGHT: align text right
 *
 * Horizontal alignment of the text.
 */
typedef enum {
    GST_TEXT_OVERLAY_HALIGN_LEFT,
    GST_TEXT_OVERLAY_HALIGN_CENTER,
    GST_TEXT_OVERLAY_HALIGN_RIGHT
} GstTextOverlayHAlign;

/**
 * GstTextOverlayWrapMode:
 * @GST_TEXT_OVERLAY_WRAP_MODE_NONE: no wrapping
 * @GST_TEXT_OVERLAY_WRAP_MODE_WORD: do word wrapping
 * @GST_TEXT_OVERLAY_WRAP_MODE_CHAR: do char wrapping
 * @GST_TEXT_OVERLAY_WRAP_MODE_WORD_CHAR: do word and char wrapping
 *
 * Whether to wrap the text and if so how.
 */
typedef enum {
    GST_TEXT_OVERLAY_WRAP_MODE_NONE = -1,
    GST_TEXT_OVERLAY_WRAP_MODE_WORD = PANGO_WRAP_WORD,
    GST_TEXT_OVERLAY_WRAP_MODE_CHAR = PANGO_WRAP_CHAR,
    GST_TEXT_OVERLAY_WRAP_MODE_WORD_CHAR = PANGO_WRAP_WORD_CHAR
} GstTextOverlayWrapMode;

/**
 * GstTextOverlay:
 *
 * Opaque textoverlay object structure
 */
struct _GstTextOverlay {
    GstElement               element;

    GstPad                  *video_sinkpad;
    GstPad                  *text_sinkpad;
    GstPad                  *srcpad;

    GstSegment              *segment;
    GstBuffer               *text_buffer;
    gboolean                text_linked;
    gboolean                video_flushing;
    gboolean                text_flushing;
  
    GCond                   *cond;  /* to signal removal of data */

    gint                     width;
    gint                     height;
    gint                     fps_n;
    gint                     fps_d;

    GstTextOverlayVAlign     valign;
    GstTextOverlayHAlign     halign;
    GstTextOverlayWrapMode   wrap_mode;

    gint                     xpad;
    gint                     ypad;
    gint                     deltax;
    gint                     deltay;
    gchar                   *default_text;
    gboolean                 want_shading;

    PangoLayout             *layout;
    FT_Bitmap                bitmap;
    gint                     bitmap_buffer_size;
    gint                     baseline_y;

    gboolean                 need_render;

    gint                     shading_value;  /* for timeoverlay subclass */

    gboolean                 have_pango_markup;
};

struct _GstTextOverlayClass {
    GstElementClass parent_class;

    PangoContext *pango_context;

    gchar *     (*get_text) (GstTextOverlay *overlay, GstBuffer *video_frame);
};

GType gst_text_overlay_get_type(void) G_GNUC_CONST;

G_END_DECLS

#endif /* __GST_TEXT_OVERLAY_H */