VSE: Media transform redesign

This patch changes behavior of strip transform and crop feature.

Purpose of this change is to allow display arbitrary portion of input
image, simplify user interface and workflow.
Offset and Crop values in old files are converted in versioning.
Offset animation is also converted. Crop animation and animation of
crop or offset enable properties is not taken into account

Changes in behavior and interface:
- If image is added to timeline it is scaled to fit inside preview area
while maintaining aspect ratio. Image is centered. This is considered
as a baseline for further transformation.
- Scale and rotation was added, so it is possible to transform image at
it's original resolution.
- Crop will not affect image transformation (does not move image).
- Values of Crop and Transform Position are in pixels, these values are
corrected if preview is fraction of project resolution.
- Transform and Mirror panel has been removed and new Transform panel
and Crop panel is moved to Adjust panel. Mirror is now part of new
Transform panel.

Technical changes:
- Preprocessing stage must work on duplicated image, because original is
cached. Previously Crop and Offset could run at once and required only
one duplication of image. This is not the case with new algorithms, so
duplication on demand is implemented. Transformation can read original
image and will output new image that is safe to modify. It should be
possible to add crop step to transform algorithm, so that Crop won't
require previous duplication though.
- Use Crop and Use Translation checkboxes were removed. Individual
values are compared to default values to check if image needs to be
processed. In case of transform this will be done also if resolution of
source.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8393

1 files changed, 75 insertions, 2 deletions

diff --git a/source/blender/imbuf/intern/rectop.c b/source/blender/imbuf/intern/rectop.c
index 8b4f33bb306..8e348ead756 100644
--- a/source/blender/imbuf/intern/rectop.c
+++ b/source/blender/imbuf/intern/rectop.c
@@ -1069,8 +1069,11 @@ void IMB_rectblend_threaded(ImBuf *dbuf,
   }
 }
 
-/* fill */
-
+/**
+ * Replace pixels of entire image with solid color.
+ * \param ibuf an image to be filled with color. It must be 4 channel image.
+ * \param col RGBA color, which is assigned directly to both byte (via scaling) and float buffers.
+ */
 void IMB_rectfill(ImBuf *drect, const float col[4])
 {
   int num;
@@ -1103,6 +1106,61 @@ void IMB_rectfill(ImBuf *drect, const float col[4])
   }
 }
 
+/**
+ * Replace pixels of image area with solid color.
+ * \param ibuf an image to be filled with color. It must be 4 channel image.
+ * \param col RGBA color, which is assigned directly to both byte (via scaling) and float buffers.
+ * \param x1, y1, x2, y2 (x1, y1) defines starting point of the rectangular area to be filled,
+ * (x2, y2) is the end point. Note that values are allowed to be loosely ordered, which means that
+ * x2 is allowed to be lower than x1, as well as y2 is allowed to be lower than y1. No matter the
+ * order the area between x1 and x2, and y1 and y2 is filled.
+ */
+void IMB_rectfill_area_replace(
+    const ImBuf *ibuf, const float col[4], int x1, int y1, int x2, int y2)
+{
+  /* Sanity checks. */
+  BLI_assert(ibuf->channels == 4);
+
+  if (ibuf->channels != 4) {
+    return;
+  }
+
+  int width = ibuf->x;
+  int height = ibuf->y;
+  CLAMP(x1, 0, width);
+  CLAMP(x2, 0, width);
+  CLAMP(y1, 0, height);
+  CLAMP(y2, 0, height);
+
+  if (x1 > x2) {
+    SWAP(int, x1, x2);
+  }
+  if (y1 > y2) {
+    SWAP(int, y1, y2);
+  }
+  if (x1 == x2 || y1 == y2) {
+    return;
+  }
+
+  unsigned char col_char[4] = {col[0] * 255, col[1] * 255, col[2] * 255, col[3] * 255};
+
+  for (int y = y1; y < y2; y++) {
+    for (int x = x1; x < x2; x++) {
+      size_t offset = ((size_t)ibuf->x) * y * 4 + 4 * x;
+
+      if (ibuf->rect) {
+        unsigned char *rrect = (unsigned char *)ibuf->rect + offset;
+        memcpy(rrect, &col_char, sizeof(unsigned char) * 4);
+      }
+
+      if (ibuf->rect_float) {
+        float *rrectf = ibuf->rect_float + offset;
+        memcpy(rrectf, &col, sizeof(float) * 4);
+      }
+    }
+  }
+}
+
 void buf_rectfill_area(unsigned char *rect,
                        float *rectf,
                        int width,
@@ -1214,6 +1272,21 @@ void buf_rectfill_area(unsigned char *rect,
   }
 }
 
+/**
+ * Blend pixels of image area with solid color.
+ *
+ * For images with uchar buffer use color matching image colorspace.
+ * For images with float buffer use color display colorspace.
+ * If display colorspace can not be referenced, use color in SRGB colorspace.
+ *
+ * \param ibuf an image to be filled with color. It must be 4 channel image.
+ * \param col RGBA color.
+ * \param x1, y1, x2, y2 (x1, y1) defines starting point of the rectangular area to be filled,
+ * (x2, y2) is the end point. Note that values are allowed to be loosely ordered, which means that
+ * x2 is allowed to be lower than x1, as well as y2 is allowed to be lower than y1. No matter the
+ * order the area between x1 and x2, and y1 and y2 is filled.
+ * \param display colorspace reference for display space.
+ */
 void IMB_rectfill_area(ImBuf *ibuf,
                        const float col[4],
                        int x1,