libavfilter: image transform code

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 125 insertions, 0 deletions

diff --git a/libavfilter/transform.h b/libavfilter/transform.h
new file mode 100644
index 0000000000..2d5cf37aa1
--- /dev/null
+++ b/libavfilter/transform.h
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2010 Georg Martius <georg.martius@web.de>
+ * Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavfilter/transform.h
+ * transform input video
+ *
+ * All matrices are defined as a single 9-item block of contiguous memory. For
+ * example, the identity matrix would be:
+ *
+ *     float *matrix = {1, 0, 0,
+ *                      0, 1, 0,
+ *                      0, 0, 1};
+ */
+
+enum InterpolateMethod {
+    INTERPOLATE_NEAREST,        //< Nearest-neighbor (fast)
+    INTERPOLATE_BILINEAR,       //< Bilinear
+    INTERPOLATE_BIQUADRATIC,    //< Biquadratic (best)
+    INTERPOLATE_COUNT,          //< Number of interpolation methods
+};
+
+// Shortcuts for the fastest and best interpolation methods
+#define INTERPOLATE_DEFAULT INTERPOLATE_BILINEAR
+#define INTERPOLATE_FAST    INTERPOLATE_NEAREST
+#define INTERPOLATE_BEST    INTERPOLATE_BIQUADRATIC
+
+enum FillMethod {
+    FILL_BLANK,         //< Fill zeroes at blank locations
+    FILL_ORIGINAL,      //< Original image at blank locations
+    FILL_CLAMP,         //< Extruded edge value at blank locations
+    FILL_MIRROR,        //< Mirrored edge at blank locations
+    FILL_COUNT,         //< Number of edge fill methods
+};
+
+// Shortcuts for fill methods
+#define FILL_DEFAULT FILL_ORIGINAL
+
+/**
+ * Get an affine transformation matrix from a given translation, rotation, and
+ * zoom factor. The matrix will look like:
+ *
+ * [ zoom * cos(angle),           -sin(angle),     x_shift,
+ *          sin(angle),     zoom * cos(angle),     y_shift,
+                     0,                     0,           1 ]
+ *
+ * Paramters:
+ *  x_shift: Horizontal translation
+ *  y_shift: Vertical translation
+ *    angle: Rotation in radians
+ *     zoom: Scale percent (1.0 = 100%)
+ *   matrix: 9-item affine transformation matrix
+ */
+void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix);
+
+/**
+ * Add two matrices together. result = m1 + m2.
+ *
+ * Parameters:
+ *      m1: 9-item transformation matrix
+ *      m2: 9-item transformation matrix
+ *  result: 9-item transformation matrix
+ */
+void avfilter_add_matrix(const float *m1, const float *m2, float *result);
+
+/**
+ * Subtract one matrix from another. result = m1 - m2.
+ *
+ * Parameters:
+ *      m1: 9-item transformation matrix
+ *      m2: 9-item transformation matrix
+ *  result: 9-item transformation matrix
+ */
+void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
+
+/**
+ * Multiply a matrix by a scalar value. result = m1 * scalar.
+ *
+ * Parameters:
+ *      m1: 9-item transformation matrix
+ *  scalar: A number
+ *  result: 9-item transformation matrix
+ */
+void avfilter_mul_matrix(const float *m1, float scalar, float *result);
+
+/**
+ * Do an affine transformation with the given interpolation method. This
+ * multiplies each vector [x,y,1] by the matrix and then interpolates to
+ * get the final value.
+ *
+ * Parameters:
+ *          src: Source image
+ *          dst: Destination image
+ *   src_stride: Source image line size in bytes
+ *   dst_stride: Destination image line size in bytes
+ *        width: Image width in pixels
+ *       height: Image height in pixels
+ *       matrix: 9-item affine transformation matrix
+ *  interpolate: Pixel interpolation method
+ *         fill: Edge fill method
+ */
+void avfilter_transform(const uint8_t *src, uint8_t *dst,
+                        int src_stride, int dst_stride,
+                        int width, int height, const float *matrix,
+                        enum InterpolateMethod interpolate,
+                        enum FillMethod fill);
+