/*
 * transition_affine.c -- affine transformations
 * Copyright (C) 2003-2022 Meltytech, LLC
 *
 * This library 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.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <framework/mlt.h>
#include <framework/mlt_transition.h>

#include <ctype.h>
#include <float.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "interp.h"

#define MLT_AFFINE_MAX_DIMENSION (16000)

static double alignment_parse(char *align)
{
    int ret = 0.0;

    if (align == NULL)
        ;
    else if (isdigit(align[0]))
        ret = atoi(align);
    else if (align[0] == 'c' || align[0] == 'm')
        ret = 1.0;
    else if (align[0] == 'r' || align[0] == 'b')
        ret = 2.0;

    return ret;
}

static mlt_position repeat_position(mlt_properties properties,
                                    const char *name,
                                    mlt_position position,
                                    int length)
{
    // Make mlt_properties parse and refresh animation.
    mlt_properties_anim_get_double(properties, name, position, length);
    mlt_animation animation = mlt_properties_get_animation(properties, name);
    if (animation) {
        // Apply repeat and mirror options.
        int anim_length = mlt_animation_get_length(animation);
        int repeat_off = mlt_properties_get_int(properties, "repeat_off");
        if (!repeat_off && position >= anim_length && anim_length != 0) {
            int section = position / anim_length;
            int mirror_off = mlt_properties_get_int(properties, "mirror_off");
            position -= section * anim_length;
            if (!mirror_off && section % 2 == 1)
                position = anim_length - position;
        }
    }
    return position;
}

static double anim_get_angle(mlt_properties properties,
                             const char *name,
                             mlt_position position,
                             mlt_position length)
{
    double result = 0.0;
    if (mlt_properties_get(properties, name)) {
        position = repeat_position(properties, name, position, length);
        result = mlt_properties_anim_get_double(properties, name, position, length);
        if (strchr(mlt_properties_get(properties, name), '%'))
            result *= 360;
    }
    return result;
}

typedef struct
{
    double matrix[3][3];
} affine_t;

static void affine_init(double affine[3][3])
{
    affine[0][0] = 1;
    affine[0][1] = 0;
    affine[0][2] = 0;
    affine[1][0] = 0;
    affine[1][1] = 1;
    affine[1][2] = 0;
    affine[2][0] = 0;
    affine[2][1] = 0;
    affine[2][2] = 1;
}

// Multiply two this affine transform with that
static void affine_multiply(double affine[3][3], double matrix[3][3])
{
    double output[3][3];
    int i;
    int j;

    for (i = 0; i < 3; i++)
        for (j = 0; j < 3; j++)
            output[i][j] = affine[i][0] * matrix[j][0] + affine[i][1] * matrix[j][1]
                           + affine[i][2] * matrix[j][2];

    affine[0][0] = output[0][0];
    affine[0][1] = output[0][1];
    affine[0][2] = output[0][2];
    affine[1][0] = output[1][0];
    affine[1][1] = output[1][1];
    affine[1][2] = output[1][2];
    affine[2][0] = output[2][0];
    affine[2][1] = output[2][1];
    affine[2][2] = output[2][2];
}

// Rotate by a given angle
static void affine_rotate_x(double affine[3][3], double angle)
{
    double matrix[3][3];
    matrix[0][0] = cos(angle * M_PI / 180);
    matrix[0][1] = 0 - sin(angle * M_PI / 180);
    matrix[0][2] = 0;
    matrix[1][0] = sin(angle * M_PI / 180);
    matrix[1][1] = cos(angle * M_PI / 180);
    matrix[1][2] = 0;
    matrix[2][0] = 0;
    matrix[2][1] = 0;
    matrix[2][2] = 1;
    affine_multiply(affine, matrix);
}

static void affine_rotate_y(double affine[3][3], double angle)
{
    double matrix[3][3];
    matrix[0][0] = cos(angle * M_PI / 180);
    matrix[0][1] = 0;
    matrix[0][2] = 0 - sin(angle * M_PI / 180);
    matrix[1][0] = 0;
    matrix[1][1] = 1;
    matrix[1][2] = 0;
    matrix[2][0] = sin(angle * M_PI / 180);
    matrix[2][1] = 0;
    matrix[2][2] = cos(angle * M_PI / 180);
    affine_multiply(affine, matrix);
}

static void affine_rotate_z(double affine[3][3], double angle)
{
    double matrix[3][3];
    matrix[0][0] = 1;
    matrix[0][1] = 0;
    matrix[0][2] = 0;
    matrix[1][0] = 0;
    matrix[1][1] = cos(angle * M_PI / 180);
    matrix[1][2] = sin(angle * M_PI / 180);
    matrix[2][0] = 0;
    matrix[2][1] = -sin(angle * M_PI / 180);
    matrix[2][2] = cos(angle * M_PI / 180);
    affine_multiply(affine, matrix);
}

static void affine_scale(double affine[3][3], double sx, double sy)
{
    double matrix[3][3];
    matrix[0][0] = sx;
    matrix[0][1] = 0;
    matrix[0][2] = 0;
    matrix[1][0] = 0;
    matrix[1][1] = sy;
    matrix[1][2] = 0;
    matrix[2][0] = 0;
    matrix[2][1] = 0;
    matrix[2][2] = 1;
    affine_multiply(affine, matrix);
}

// Shear by a given value
static void affine_shear(double affine[3][3], double shear_x, double shear_y, double shear_z)
{
    double matrix[3][3];
    matrix[0][0] = 1;
    matrix[0][1] = tan(shear_x * M_PI / 180);
    matrix[0][2] = 0;
    matrix[1][0] = tan(shear_y * M_PI / 180);
    matrix[1][1] = 1;
    matrix[1][2] = tan(shear_z * M_PI / 180);
    matrix[2][0] = 0;
    matrix[2][1] = 0;
    matrix[2][2] = 1;
    affine_multiply(affine, matrix);
}

static void affine_offset(double affine[3][3], double x, double y)
{
    affine[0][2] += x;
    affine[1][2] += y;
}

// Obtain the mapped x coordinate of the input
static inline double MapX(double affine[3][3], double x, double y)
{
    return affine[0][0] * x + affine[0][1] * y + affine[0][2];
}

// Obtain the mapped y coordinate of the input
static inline double MapY(double affine[3][3], double x, double y)
{
    return affine[1][0] * x + affine[1][1] * y + affine[1][2];
}

static inline double MapZ(double affine[3][3], double x, double y)
{
    return affine[2][0] * x + affine[2][1] * y + affine[2][2];
}

static void affine_max_output(
    double affine[3][3], double *w, double *h, double dz, double max_width, double max_height)
{
    int tlx = MapX(affine, -max_width, max_height) / dz;
    int tly = MapY(affine, -max_width, max_height) / dz;
    int trx = MapX(affine, max_width, max_height) / dz;
    int try = MapY(affine, max_width, max_height) / dz;
    int blx = MapX(affine, -max_width, -max_height) / dz;
    int bly = MapY(affine, -max_width, -max_height) / dz;
    int brx = MapX(affine, max_width, -max_height) / dz;
    int bry = MapY(affine, max_width, -max_height) / dz;

    int max_x;
    int max_y;
    int min_x;
    int min_y;

    max_x = MAX(tlx, trx);
    max_x = MAX(max_x, blx);
    max_x = MAX(max_x, brx);

    min_x = MIN(tlx, trx);
    min_x = MIN(min_x, blx);
    min_x = MIN(min_x, brx);

    max_y = MAX(tly, try);
    max_y = MAX(max_y, bly);
    max_y = MAX(max_y, bry);

    min_y = MIN(tly, try);
    min_y = MIN(min_y, bly);
    min_y = MIN(min_y, bry);

    *w = (double) (max_x - min_x + 1) / max_width / 2.0;
    *h = (double) (max_y - min_y + 1) / max_height / 2.0;
}

#define IN_RANGE(v, r) (v >= -r / 2 && v < r / 2)

static inline void get_affine(affine_t *affine,
                              mlt_transition transition,
                              double position,
                              int length,
                              double scale_width,
                              double scale_height)
{
    mlt_properties properties = MLT_TRANSITION_PROPERTIES(transition);
    int keyed = mlt_properties_get_int(properties, "keyed");

    if (keyed == 0) {
        double fix_rotate_x = anim_get_angle(properties, "fix_rotate_x", position, length);
        double fix_rotate_y = anim_get_angle(properties, "fix_rotate_y", position, length);
        double fix_rotate_z = anim_get_angle(properties, "fix_rotate_z", position, length);
        double rotate_x = mlt_properties_get_double(properties, "rotate_x");
        double rotate_y = mlt_properties_get_double(properties, "rotate_y");
        double rotate_z = mlt_properties_get_double(properties, "rotate_z");
        double fix_shear_x = anim_get_angle(properties, "fix_shear_x", position, length);
        double fix_shear_y = anim_get_angle(properties, "fix_shear_y", position, length);
        double fix_shear_z = anim_get_angle(properties, "fix_shear_z", position, length);
        double shear_x = mlt_properties_get_double(properties, "shear_x");
        double shear_y = mlt_properties_get_double(properties, "shear_y");
        double shear_z = mlt_properties_get_double(properties, "shear_z");
        double ox = mlt_properties_anim_get_double(properties, "ox", position, length);
        double oy = mlt_properties_anim_get_double(properties, "oy", position, length);

        affine_rotate_x(affine->matrix, fix_rotate_x + rotate_x * position);
        affine_rotate_y(affine->matrix, fix_rotate_y + rotate_y * position);
        affine_rotate_z(affine->matrix, fix_rotate_z + rotate_z * position);
        affine_shear(affine->matrix,
                     fix_shear_x + shear_x * position,
                     fix_shear_y + shear_y * position,
                     fix_shear_z + shear_z * position);
        affine_offset(affine->matrix, ox * scale_width, oy * scale_height);
    } else {
        double rotate_x = anim_get_angle(properties, "rotate_x", position, length);
        double rotate_y = anim_get_angle(properties, "rotate_y", position, length);
        double rotate_z = anim_get_angle(properties, "rotate_z", position, length);
        double shear_x = anim_get_angle(properties, "shear_x", position, length);
        double shear_y = anim_get_angle(properties, "shear_y", position, length);
        double shear_z = anim_get_angle(properties, "shear_z", position, length);
        double o_x
            = mlt_properties_anim_get_double(properties,
                                             "ox",
                                             repeat_position(properties, "ox", position, length),
                                             length);
        double o_y
            = mlt_properties_anim_get_double(properties,
                                             "oy",
                                             repeat_position(properties, "oy", position, length),
                                             length);

        affine_rotate_x(affine->matrix, rotate_x);
        affine_rotate_y(affine->matrix, rotate_y);
        affine_rotate_z(affine->matrix, rotate_z);
        affine_shear(affine->matrix, shear_x, shear_y, shear_z);
        affine_offset(affine->matrix, o_x * scale_width, o_y * scale_height);
    }
}

struct sliced_desc
{
    uint8_t *a_image, *b_image;
    interpp interp;
    affine_t affine;
    int a_width, a_height, b_width, b_height;
    double lower_x, lower_y;
    double dz, mix;
    double x_offset, y_offset;
    int b_alpha;
    double minima, xmax, ymax;
};

static int sliced_proc(int id, int index, int jobs, void *cookie)
{
    (void) id; // unused
    struct sliced_desc ctx = *((struct sliced_desc *) cookie);
    int starty, height_slice = mlt_slices_size_slice(jobs, index, ctx.a_height, &starty);
    double x, y;
    double dx, dy;
    int i, j;

    ctx.a_image += starty * (ctx.a_width * 4);
    for (i = 0, y = ctx.lower_y; i < ctx.a_height; i++, y++) {
        if (i >= starty && i < (starty + height_slice)) {
            for (j = 0, x = ctx.lower_x; j < ctx.a_width; j++, x++) {
                dx = MapX(ctx.affine.matrix, x, y) / ctx.dz + ctx.x_offset;
                dy = MapY(ctx.affine.matrix, x, y) / ctx.dz + ctx.y_offset;
                if (dx >= ctx.minima && dx <= ctx.xmax && dy >= ctx.minima && dy <= ctx.ymax)
                    ctx.interp(ctx.b_image,
                               ctx.b_width,
                               ctx.b_height,
                               dx,
                               dy,
                               ctx.mix,
                               ctx.a_image,
                               ctx.b_alpha);
                ctx.a_image += 4;
            }
        }
    }
    return 0;
}

/** Get the image.
*/

static int transition_get_image(mlt_frame a_frame,
                                uint8_t **image,
                                mlt_image_format *format,
                                int *width,
                                int *height,
                                int writable)
{
    // Get the b frame from the stack
    mlt_frame b_frame = mlt_frame_pop_frame(a_frame);

    // Get the transition object
    mlt_transition transition = mlt_frame_pop_service(a_frame);

    // Get the properties of the transition
    mlt_properties properties = MLT_TRANSITION_PROPERTIES(transition);

    // Get the properties of the a frame
    mlt_properties a_props = MLT_FRAME_PROPERTIES(a_frame);

    // Get the properties of the b frame
    mlt_properties b_props = MLT_FRAME_PROPERTIES(b_frame);

    // Image, format, width, height and image for the b frame
    uint8_t *b_image = NULL;
    mlt_image_format b_format = mlt_image_rgba;
    int b_width = mlt_properties_get_int(b_props, "meta.media.width");
    int b_height = mlt_properties_get_int(b_props, "meta.media.height");
    double b_ar = mlt_frame_get_aspect_ratio(b_frame);
    double b_dar = b_ar * b_width / b_height;

    // Assign the current position
    mlt_position position = mlt_transition_get_position(transition, a_frame);

    int mirror = mlt_properties_get_position(properties, "mirror");
    int length = mlt_transition_get_length(transition);
    if (mlt_properties_get_int(properties, "always_active")) {
        mlt_properties props = mlt_properties_get_data(b_props, "_producer", NULL);
        mlt_position in = mlt_properties_get_int(props, "in");
        mlt_position out = mlt_properties_get_int(props, "out");
        length = out - in + 1;
    }

    // Obtain the normalized width and height from the a_frame
    mlt_profile profile = mlt_service_profile(MLT_TRANSITION_SERVICE(transition));
    int normalized_width = profile->width;
    int normalized_height = profile->height;
    double consumer_ar = mlt_profile_sar(profile);

    if (mirror && position > length / 2)
        position = abs(position - length);

    // Preview scaling is not working correctly when offsets are active. I have
    // not figured out the math; so, disable preview scaling for now.
    double ox = mlt_properties_anim_get_double(properties, "ox", position, length);
    double oy = mlt_properties_anim_get_double(properties, "oy", position, length);
    if (ox != 0.0 || oy != 0.0) {
        *width = normalized_width;
        *height = normalized_height;
    }

    // Fetch the a frame image
    *format = mlt_image_rgba;
    int error = mlt_frame_get_image(a_frame, image, format, width, height, 1);
    if (error || !image)
        return error;

    // Calculate the region now
    double scale_width = mlt_profile_scale_width(profile, *width);
    double scale_height = mlt_profile_scale_height(profile, *height);
    mlt_rect result = {0, 0, normalized_width, normalized_height, 1.0};

    mlt_service_lock(MLT_TRANSITION_SERVICE(transition));

    if (mlt_properties_get(properties, "rect")) {
        // Determine length and obtain cycle
        double cycle = mlt_properties_get_double(properties, "cycle");

        // Allow a repeat cycle
        if (cycle >= 1)
            length = cycle;
        else if (cycle > 0)
            length *= cycle;

        mlt_position anim_pos = repeat_position(properties, "rect", position, length);
        result = mlt_properties_anim_get_rect(properties, "rect", anim_pos, length);
        if (mlt_properties_get(properties, "rect")
            && strchr(mlt_properties_get(properties, "rect"), '%')) {
            result.x *= normalized_width;
            result.y *= normalized_height;
            result.w *= normalized_width;
            result.h *= normalized_height;
        }
        result.o = (result.o == DBL_MIN) ? 1.0 : MIN(result.o, 1.0);
    }

    int threads = mlt_properties_get_int(properties, "threads");
    threads = CLAMP(threads, 0, mlt_slices_count_normal());
    if (threads == 1)
        mlt_service_unlock(MLT_TRANSITION_SERVICE(transition));

    result.x *= scale_width;
    result.y *= scale_height;
    result.w *= scale_width;
    result.h *= scale_height;

    double geometry_w = result.w;
    double geometry_h = result.h;
    int fill = mlt_properties_get_int(properties, "fill");
    int distort = mlt_properties_get_int(properties, "distort");

    if (!fill) {
        double geometry_dar = result.w * consumer_ar / result.h;

        if (b_dar > geometry_dar) {
            result.w = MIN(result.w, b_width * b_ar / consumer_ar);
            result.h = result.w * consumer_ar / b_dar;
        } else {
            result.h = MIN(result.h, b_height);
            result.w = result.h * b_dar / consumer_ar;
        }
    }

    // Fetch the b frame image
    if (scale_width != 1.0 || scale_height != 1.0) {
        // Scale request of b frame image to consumer scale maintaining its aspect ratio.
        b_height = CLAMP(*height, 1, MLT_AFFINE_MAX_DIMENSION);
        b_width = MAX(b_height * b_dar / b_ar, 1);
        if (b_width > MLT_AFFINE_MAX_DIMENSION) {
            b_width = CLAMP(*width, 1, MLT_AFFINE_MAX_DIMENSION);
            b_height = MAX(b_width * b_ar / b_dar, 1);
        }
        // Set the rescale interpolation to match the frame
        mlt_properties_set(b_props,
                           "consumer.rescale",
                           mlt_properties_get(a_props, "consumer.rescale"));
        // Disable padding (resize filter)
        mlt_properties_set_int(b_props, "distort", 1);
    } else if (mlt_properties_get_int(b_props, "always_scale")
               || (!mlt_properties_get_int(b_props, "interpolation_not_required")
                   && (fill || distort || b_width > result.w || b_height > result.h
                       || mlt_properties_get_int(properties, "b_scaled")))) {
        // Request b frame image scaled to what is needed.
        b_height = CLAMP(result.h, 1, MLT_AFFINE_MAX_DIMENSION);
        b_width = MAX(b_height * b_dar / b_ar, 1);
        if (b_width > MLT_AFFINE_MAX_DIMENSION) {
            b_width = CLAMP(result.w, 1, MLT_AFFINE_MAX_DIMENSION);
            b_height = MAX(b_width * b_ar / b_dar, 1);
        }
        // Set the rescale interpolation to match the frame
        mlt_properties_set(b_props,
                           "consumer.rescale",
                           mlt_properties_get(a_props, "consumer.rescale"));
        // Disable padding (resize filter)
        mlt_properties_set_int(b_props, "distort", 1);
    } else {
        // Request at resolution of b frame image. This only happens when not using fill or distort mode
        // and the image is smaller than the rect with the intention to prevent scaling of the
        // image and merely position and possibly transform.
        mlt_properties_set_int(b_props, "rescale_width", b_width);
        mlt_properties_set_int(b_props, "rescale_height", b_height);

        const char *b_resource = mlt_properties_get(MLT_PRODUCER_PROPERTIES(
                                                        mlt_frame_get_original_producer(b_frame)),
                                                    "resource");
        // Check if we are applied as a filter inside a transition
        if (b_resource && !strcmp("<track>", b_resource)) {
            // Set the rescale interpolation to match the frame
            mlt_properties_set(b_props,
                               "consumer.rescale",
                               mlt_properties_get(a_props, "consumer.rescale"));
        } else {
            // Suppress padding and aspect normalization.
            mlt_properties_set(b_props, "consumer.rescale", "none");
        }
    }
    mlt_log_debug(MLT_TRANSITION_SERVICE(transition),
                  "requesting image B at resolution %dx%d\n",
                  b_width,
                  b_height);

    // This is not a field-aware transform.
    mlt_properties_set_int(b_props, "consumer.progressive", 1);

    error = mlt_frame_get_image(b_frame, &b_image, &b_format, &b_width, &b_height, 0);
    if (error || !b_image) {
        // Remove potentially large image on the B frame.
        mlt_frame_set_image(b_frame, NULL, 0, NULL);
        if (threads != 1)
            mlt_service_unlock(MLT_TRANSITION_SERVICE(transition));
        return error;
    }

    // Check that both images are of the correct format and process
    if (*format == mlt_image_rgba && b_format == mlt_image_rgba) {
        double sw, sh;
        // Get values from the transition
        double scale_x = mlt_properties_anim_get_double(properties, "scale_x", position, length);
        double scale_y = mlt_properties_anim_get_double(properties, "scale_y", position, length);
        int scale = mlt_properties_get_int(properties, "scale");
        double geom_scale_x = (double) b_width / result.w;
        double geom_scale_y = (double) b_height / result.h;
        struct sliced_desc desc = {.a_image = *image,
                                   .b_image = b_image,
                                   .interp = interpBL_b32,
                                   .a_width = *width,
                                   .a_height = *height,
                                   .b_width = b_width,
                                   .b_height = b_height,
                                   .lower_x = -(result.x + result.w / 2.0), // center
                                   .lower_y = -(result.y + result.h / 2.0), // middle
                                   .mix = result.o,
                                   .x_offset = (double) b_width / 2.0,
                                   .y_offset = (double) b_height / 2.0,
                                   .b_alpha = mlt_properties_get_int(properties, "b_alpha"),
                                   // Affine boundaries
                                   .minima = 0,
                                   .xmax = b_width - 1,
                                   .ymax = b_height - 1};

        // Recalculate vars if alignment supplied.
        if (mlt_properties_get(properties, "halign") || mlt_properties_get(properties, "valign")) {
            double halign = alignment_parse(mlt_properties_get(properties, "halign"));
            double valign = alignment_parse(mlt_properties_get(properties, "valign"));
            desc.x_offset = halign * b_width / 2.0;
            desc.y_offset = valign * b_height / 2.0;
            desc.lower_x = -(result.x + geometry_w * halign / 2.0f);
            desc.lower_y = -(result.y + geometry_h * valign / 2.0f);
        }

        affine_init(desc.affine.matrix);

        // Compute the affine transform
        get_affine(&desc.affine, transition, (double) position, length, scale_width, scale_height);
        desc.dz = MapZ(desc.affine.matrix, 0, 0);
        if ((int) fabs(desc.dz * 1000) < 25) {
            if (threads != 1)
                mlt_service_unlock(MLT_TRANSITION_SERVICE(transition));
            return 0;
        }

        if (mlt_properties_get_int(properties, "invert_scale")) {
            scale_x = 1.0 / scale_x;
            scale_y = 1.0 / scale_y;
        }

        // Factor scaling into the transformation based on output resolution.
        if (distort) {
            scale_x = geom_scale_x * (scale_x == 0 ? 1 : scale_x);
            scale_y = geom_scale_y * (scale_y == 0 ? 1 : scale_y);
        } else {
            // Determine scale with respect to aspect ratio.
            double consumer_dar = consumer_ar * normalized_width / normalized_height;

            if (b_dar > consumer_dar) {
                scale_x = geom_scale_x * (scale_x == 0 ? 1 : scale_x);
                scale_y = geom_scale_x * (scale_y == 0 ? 1 : scale_y);
                scale_y *= b_ar / consumer_ar;
            } else {
                scale_x = geom_scale_y * (scale_x == 0 ? 1 : scale_x);
                scale_y = geom_scale_y * (scale_y == 0 ? 1 : scale_y);
                scale_x *= consumer_ar / b_ar;
            }
        }
        if (scale) {
            affine_max_output(desc.affine.matrix, &sw, &sh, desc.dz, *width, *height);
            affine_scale(desc.affine.matrix,
                         sw * MIN(geom_scale_x, geom_scale_y),
                         sh * MIN(geom_scale_x, geom_scale_y));
        } else if (scale_x != 0 && scale_y != 0) {
            affine_scale(desc.affine.matrix, scale_x, scale_y);
        }

        char *interps = mlt_properties_get(a_props, "consumer.rescale");
        // Copy in case string is changed.
        if (interps)
            interps = strdup(interps);

        // Set the interpolation function
        if (interps == NULL || strcmp(interps, "nearest") == 0 || strcmp(interps, "neighbor") == 0
            || strcmp(interps, "tiles") == 0 || strcmp(interps, "fast_bilinear") == 0) {
            desc.interp = interpNN_b32;
            // uses lrintf. Values should be >= -0.5 and < max + 0.5
            desc.minima -= 0.5;
            desc.xmax += 0.49;
            desc.ymax += 0.49;
        } else if (strcmp(interps, "bilinear") == 0) {
            desc.interp = interpBL_b32;
            // uses floorf.
        } else if (strcmp(interps, "bicubic") == 0 || strcmp(interps, "hyper") == 0
                   || strcmp(interps, "sinc") == 0 || strcmp(interps, "lanczos") == 0
                   || strcmp(interps, "spline") == 0) {
            // TODO: lanczos 8x8
            // TODO: spline 4x4 or 6x6
            desc.interp = interpBC_b32;
            // uses ceilf. Values should be > -1 and <= max.
            desc.minima -= 1;
        }
        free(interps);

        // Do the transform with interpolation
        if (threads == 1)
            sliced_proc(0, 0, 1, &desc);
        else
            mlt_slices_run_normal(threads, sliced_proc, &desc);

        // Remove potentially large image on the B frame.
        mlt_frame_set_image(b_frame, NULL, 0, NULL);
    }
    if (threads != 1)
        mlt_service_unlock(MLT_TRANSITION_SERVICE(transition));
    return 0;
}

/** Affine transition processing.
*/

static mlt_frame transition_process(mlt_transition transition, mlt_frame a_frame, mlt_frame b_frame)
{
    // Push the transition on to the frame
    mlt_frame_push_service(a_frame, transition);

    // Push the b_frame on to the stack
    mlt_frame_push_frame(a_frame, b_frame);

    // Push the transition method
    mlt_frame_push_get_image(a_frame, transition_get_image);

    return a_frame;
}

/** Constructor for the filter.
*/

mlt_transition transition_affine_init(mlt_profile profile,
                                      mlt_service_type type,
                                      const char *id,
                                      char *arg)
{
    mlt_transition transition = mlt_transition_new();
    if (transition != NULL) {
        mlt_properties_set_int(MLT_TRANSITION_PROPERTIES(transition), "distort", 0);
        mlt_properties_set(MLT_TRANSITION_PROPERTIES(transition),
                           "rect",
                           arg ? arg : "0%/0%:100%x100%:100%");
        // Inform apps and framework that this is a video only transition
        mlt_properties_set_int(MLT_TRANSITION_PROPERTIES(transition), "_transition_type", 1);
        mlt_properties_set_int(MLT_TRANSITION_PROPERTIES(transition), "fill", 1);
        transition->process = transition_process;
    }
    return transition;
}
