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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/overlay_transform_utils.h"
#include "base/notreached.h"
#include "ui/gfx/geometry/rect_conversions.h"
namespace gfx {
Transform OverlayTransformToTransform(OverlayTransform overlay_transform,
const SizeF& viewport_bounds) {
switch (overlay_transform) {
case OVERLAY_TRANSFORM_INVALID:
NOTREACHED();
case OVERLAY_TRANSFORM_NONE:
return Transform();
case OVERLAY_TRANSFORM_FLIP_HORIZONTAL:
return Transform::Affine(-1, 0, 0, 1, viewport_bounds.width(), 0);
case OVERLAY_TRANSFORM_FLIP_VERTICAL:
return Transform::Affine(1, 0, 0, -1, 0, viewport_bounds.height());
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_90:
return Transform::Affine(0, 1, -1, 0, viewport_bounds.height(), 0);
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_180:
return Transform::Affine(-1, 0, 0, -1, viewport_bounds.width(),
viewport_bounds.height());
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_270:
return Transform::Affine(0, -1, 1, 0, 0, viewport_bounds.width());
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_90:
return Transform::Affine(0, 1, 1, 0, 0, 0);
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_270:
return Transform::Affine(0, -1, -1, 0, viewport_bounds.height(),
viewport_bounds.width());
}
NOTREACHED();
}
OverlayTransform InvertOverlayTransform(OverlayTransform transform) {
switch (transform) {
case OVERLAY_TRANSFORM_INVALID:
NOTREACHED();
case OVERLAY_TRANSFORM_NONE:
return OVERLAY_TRANSFORM_NONE;
case OVERLAY_TRANSFORM_FLIP_HORIZONTAL:
return OVERLAY_TRANSFORM_FLIP_HORIZONTAL;
case OVERLAY_TRANSFORM_FLIP_VERTICAL:
return OVERLAY_TRANSFORM_FLIP_VERTICAL;
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_90:
return OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_270;
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_180:
return OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_180;
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_270:
return OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_90;
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_90:
return OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_90;
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_270:
return OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_270;
}
NOTREACHED();
}
OverlayTransform OverlayTransformsConcat(OverlayTransform t1,
OverlayTransform t2) {
if (t1 == OVERLAY_TRANSFORM_INVALID || t2 == OVERLAY_TRANSFORM_INVALID) {
return OVERLAY_TRANSFORM_INVALID;
}
enum VFlip {
// Written so they behave similar to bools.
kNo = 0,
kYes,
};
enum Rotation {
// Enums are written so that it's valid to do modular arithematic.
// Eg k90 + k270 mod 4 is k0.
k0 = 0,
k90,
k180,
k270,
};
// Step 1: Decompose arguments into vertical flip and clock-wise rotation.
struct DecomposedOverlayTransform {
VFlip vflip;
Rotation rotation;
};
auto decompose = [](OverlayTransform t) -> DecomposedOverlayTransform {
switch (t) {
case OVERLAY_TRANSFORM_NONE:
return {VFlip::kNo, Rotation::k0};
case OVERLAY_TRANSFORM_FLIP_HORIZONTAL:
return {VFlip::kYes, Rotation::k180};
case OVERLAY_TRANSFORM_FLIP_VERTICAL:
return {VFlip::kYes, Rotation::k0};
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_90:
return {VFlip::kNo, Rotation::k90};
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_180:
return {VFlip::kNo, Rotation::k180};
case OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_270:
return {VFlip::kNo, Rotation::k270};
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_90:
return {VFlip::kYes, Rotation::k90};
case OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_270:
return {VFlip::kYes, Rotation::k270};
case OVERLAY_TRANSFORM_INVALID:
break;
}
NOTREACHED();
};
DecomposedOverlayTransform decomposed1 = decompose(t1);
DecomposedOverlayTransform decomposed2 = decompose(t2);
// Step 2: Compute decomposed result.
// Result flip is effectively an XOR of two arguments.
VFlip result_vflip =
static_cast<VFlip>(decomposed1.vflip != decomposed2.vflip);
// Add rotation, except that rotation of `t1` needs to be subtracted if `t2`
// contains a flip.
Rotation result_rotation;
if (decomposed2.vflip == VFlip::kYes) {
result_rotation = static_cast<Rotation>(
(decomposed2.rotation + 4 - decomposed1.rotation) % 4);
} else {
result_rotation = static_cast<Rotation>(
(decomposed2.rotation + decomposed1.rotation) % 4);
}
// Step 3: Reconstruct result.
switch (result_rotation) {
case Rotation::k0:
return result_vflip == VFlip::kYes ? OVERLAY_TRANSFORM_FLIP_VERTICAL
: OVERLAY_TRANSFORM_NONE;
case Rotation::k90:
return result_vflip == VFlip::kYes
? OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_90
: OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_90;
case Rotation::k180:
return result_vflip == VFlip::kYes
? OVERLAY_TRANSFORM_FLIP_HORIZONTAL
: OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_180;
case Rotation::k270:
return result_vflip == VFlip::kYes
? OVERLAY_TRANSFORM_FLIP_VERTICAL_CLOCKWISE_270
: OVERLAY_TRANSFORM_ROTATE_CLOCKWISE_270;
}
NOTREACHED();
}
} // namespace gfx
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