Add linescan plugin for line scan camera simulation

- New plugin extracts single row/column from frames and builds line scan image - Supports horizontal mode (extract row, stack vertically) - Supports vertical mode (extract column, stack horizontally) - Configurable line index and output size - Proper caps negotiation with fixate_caps implementation - Updated build system to include linescan plugin - Added comprehensive README with usage examples
2025-11-18 01:10:47 +02:00
parent 07673f3f36
commit b19babd038
8 changed files with 1119 additions and 5 deletions
--- a/gst/linescan/gstlinescan.h
+++ b/gst/linescan/gstlinescan.h
@@ -0,0 +1,87 @@
+/* GStreamer
+ * Copyright (C) 2024 FIXME <fixme@example.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_LINESCAN_H__
+#define __GST_LINESCAN_H__
+
+#include <gst/base/gstbasetransform.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_LINESCAN \
+  (gst_linescan_get_type())
+#define GST_LINESCAN(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LINESCAN,GstLinescan))
+#define GST_LINESCAN_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_LINESCAN,GstLinescanClass))
+#define GST_IS_LINESCAN(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LINESCAN))
+#define GST_IS_LINESCAN_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_LINESCAN))
+
+typedef struct _GstLinescan GstLinescan;
+typedef struct _GstLinescanClass GstLinescanClass;
+
+typedef enum {
+  GST_LINESCAN_DIRECTION_HORIZONTAL = 0,  /* Extract row from each frame, stack vertically (width=input, height=output_size) */
+  GST_LINESCAN_DIRECTION_VERTICAL         /* Extract column from each frame, stack horizontally (width=output_size, height=input) */
+} GstLinescanDirection;
+
+/**
+ * GstLinescan:
+ * @element: the parent element.
+ *
+ * Line scan plugin that extracts a single row or column from each frame
+ * and builds them into an output image over time.
+ */
+struct _GstLinescan
+{
+  GstBaseTransform element;
+
+  /* Properties */
+  GstLinescanDirection direction;  /* HORIZONTAL or VERTICAL */
+  gint line_index;                 /* Which row/column to extract (-1 = middle) */
+  gint output_size;                /* Number of lines to accumulate (width for vertical, height for horizontal) */
+
+  /* Video info */
+  GstVideoInfo video_info_in;
+  GstVideoInfo video_info_out;
+  gboolean video_info_valid;
+
+  /* Internal state */
+  guint8 *line_buffer;             /* Buffer to accumulate lines */
+  gint buffer_position;            /* Current position in buffer (how many lines accumulated) */
+  gsize line_size;                 /* Size of one line in bytes */
+  gint actual_line_index;          /* Computed line index to extract */
+  guint64 frame_count;             /* Number of frames processed */
+  
+  gboolean output_caps_set;        /* Whether output caps have been negotiated */
+};
+
+struct _GstLinescanClass
+{
+  GstBaseTransformClass parent_class;
+};
+
+GType gst_linescan_get_type(void);
+
+G_END_DECLS
+
+#endif /* __GST_LINESCAN_H__ */