Merge branch 'vector_clip_actions' into feature

src/command/vis_tool.cpp

@@ -23,6 +23,7 @@
 #include "../visual_tool_clip.h"
 #include "../visual_tool_cross.h"
 #include "../visual_tool_drag.h"
+#include "../visual_tool_perspective.h"
 #include "../visual_tool_rotatexy.h"
 #include "../visual_tool_rotatez.h"
 #include "../visual_tool_scale.h"
@@ -100,6 +101,14 @@ namespace {
 		STR_HELP("Rotate subtitles on their X and Y axes")
 	};
 
+	struct visual_mode_perspective final : public visual_tool_command<VisualToolPerspective> {
+		CMD_NAME("video/tool/perspective")
+		CMD_ICON(visual_vector_clip_drag) //TODO
+		STR_MENU("Apply 3D Perspective")
+		STR_DISP("Apply 3D Perspective")
+		STR_HELP("Rotate and shear subtitles to make them fit a given quad's perspective")
+	};
+
 	struct visual_mode_scale final : public visual_tool_command<VisualToolScale> {
 		CMD_NAME("video/tool/scale")
 		CMD_ICON(visual_scale)
@@ -191,6 +200,7 @@ namespace cmd {
 		reg(agi::make_unique<visual_mode_drag>());
 		reg(agi::make_unique<visual_mode_rotate_z>());
 		reg(agi::make_unique<visual_mode_rotate_xy>());
+		reg(agi::make_unique<visual_mode_perspective>());
 		reg(agi::make_unique<visual_mode_scale>());
 		reg(agi::make_unique<visual_mode_clip>());
 		reg(agi::make_unique<visual_mode_vector_clip>());

src/libresrc/default_toolbar.json

@@ -73,6 +73,7 @@
         "video/tool/drag",
         "video/tool/rotate/z",
         "video/tool/rotate/xy",
+        "video/tool/perspective",
         "video/tool/scale",
         "video/tool/clip",
         "video/tool/vector_clip",

src/meson.build

@@ -144,6 +144,7 @@ aegisub_src = files(
     'utils.cpp',
     'validators.cpp',
     'vector2d.cpp',
+    'vector3d.cpp',
     'version.cpp',
     'video_box.cpp',
     'video_controller.cpp',
@@ -160,6 +161,7 @@ aegisub_src = files(
     'visual_tool_clip.cpp',
     'visual_tool_cross.cpp',
     'visual_tool_drag.cpp',
+    'visual_tool_perspective.cpp',
     'visual_tool_rotatexy.cpp',
     'visual_tool_rotatez.cpp',
     'visual_tool_scale.cpp',

src/vector3d.cpp

@@ -0,0 +1,99 @@
+// Copyright (c) 2022, arch1t3cht <arch1t3cht@gmail.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+/// @file vector3d.cpp
+/// @brief 3D mathematical vector used in visual typesetting
+/// @ingroup utility visual_ts
+///
+
+#include "vector3d.h"
+
+#include "utils.h"
+
+#include <libaegisub/format.h>
+
+#include <cmath>
+#include <limits>
+
+Vector3D::Vector3D()
+: x(std::numeric_limits<float>::min())
+, y(std::numeric_limits<float>::min())
+, z(std::numeric_limits<float>::min())
+{
+}
+
+Vector3D operator *(float f, Vector3D v) {
+	return Vector3D(v.X() * f, v.Y() * f, v.Z() * f);
+}
+
+Vector3D operator /(float f, Vector3D v) {
+	return Vector3D(f / v.X(), f / v.Y(), f / v.Z());
+}
+
+Vector3D operator +(float f, Vector3D v) {
+	return Vector3D(v.X() + f, v.Y() + f, v.Z() + f);
+}
+
+Vector3D operator -(float f, Vector3D v) {
+	return Vector3D(f - v.X(), f - v.Y(), f - v.Z());
+}
+
+Vector3D Vector3D::Unit() const {
+	float len = Len();
+	if (len == 0)
+		return Vector3D(0, 0, 0);
+	return *this / len;
+}
+
+Vector3D Vector3D::RotateX(float angle) const {
+	return Vector3D(x, y * cos(angle) - z * sin(angle), y * sin(angle) + z * cos(angle));
+}
+
+Vector3D Vector3D::RotateY(float angle) const {
+	return Vector3D(x * cos(angle) - z * sin(angle), y, x * sin(angle) + z * cos(angle));
+}
+
+Vector3D Vector3D::RotateZ(float angle) const {
+	return Vector3D(x * cos(angle) - y * sin(angle), x * sin(angle) + y * cos(angle), z);
+}
+
+Vector3D Vector3D::Max(Vector3D param) const {
+	return Vector3D(std::max(x, param.x), std::max(y, param.y), std::max(z, param.z));
+}
+
+Vector3D Vector3D::Min(Vector3D param) const {
+	return Vector3D(std::min(x, param.x), std::min(y, param.y), std::max(z, param.z));
+}
+
+Vector3D Vector3D::Round(float step) const {
+	return Vector3D(floorf(x / step + .5f) * step, floorf(y / step + .5f) * step, floorf(z / step + .5f));
+}
+
+Vector3D::operator bool() const {
+	return *this != Vector3D();
+}
+
+std::string Vector3D::PStr(char sep) const {
+	return "(" + Str(sep) + ")";
+}
+
+std::string Vector3D::DStr(char sep) const {
+	return agi::format("%d%c%d%c%d", (int)x, sep, (int)y, sep, (int)z);
+}
+
+std::string Vector3D::Str(char sep) const {
+	return float_to_string(x,2) + sep + float_to_string(y,2) + sep + float_to_string(z, 2);
+}

src/vector3d.h

@@ -0,0 +1,83 @@
+// Copyright (c) 2022,  arch1t3cht <arch1t3cht@gmail.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+/// @file vector3d.h
+/// @see vector3d.cpp
+/// @ingroup utility visual_ts
+///
+
+#pragma once
+
+#include <cmath>
+#include <string>
+#include "vector2d.h"
+
+class Vector3D {
+	float x, y, z;
+
+public:
+	float X() const { return x; }
+	float Y() const { return y; }
+	float Z() const { return z; }
+	Vector2D XY() const { return Vector2D(x, y); }
+
+	Vector3D();
+	Vector3D(Vector2D xy) : x(xy.X()), y(xy.Y()), z(0.) { }
+	Vector3D(Vector2D xy, float z) : x(xy.X()), y(xy.Y()), z(z) { }
+	Vector3D(float x, float y, float z) : x(x), y(y), z(z) { }
+
+	bool operator ==(const Vector3D r) const { return x == r.x && y == r.y; }
+	bool operator !=(const Vector3D r) const { return x != r.x || y != r.y; }
+	explicit operator bool() const;
+
+	Vector3D operator -() const { return Vector3D(-x, -y, -z); }
+	Vector3D operator +(const Vector3D r) const { return Vector3D(x + r.x, y + r.y, z + r.z); }
+	Vector3D operator -(const Vector3D r) const { return Vector3D(x - r.x, y - r.y, z - r.z); }
+	Vector3D operator *(const Vector3D r) const { return Vector3D(x * r.x, y * r.y, z * r.z); }
+	Vector3D operator /(const Vector3D r) const { return Vector3D(x / r.x, y / r.y, z / r.z); }
+	Vector3D operator +(float param) const { return Vector3D(x + param, y + param, z + param); }
+	Vector3D operator -(float param) const { return Vector3D(x - param, y - param, z - param); }
+	Vector3D operator *(float param) const { return Vector3D(x * param, y * param, z * param); }
+	Vector3D operator /(float param) const { return Vector3D(x / param, y / param, z / param); }
+
+	Vector3D Unit() const;
+
+	Vector3D RotateX(float angle) const;
+	Vector3D RotateY(float angle) const;
+	Vector3D RotateZ(float angle) const;
+
+	Vector3D Max(Vector3D param) const;
+	Vector3D Min(Vector3D param) const;
+	Vector3D Round(float step) const;
+
+	Vector3D Cross(const Vector3D param) const { return Vector3D(y * param.z - z * param.y, z * param.x - x * param.z, x * param.y - y * param.x); }
+	float Dot(const Vector3D param) const { return x * param.x + y * param.y + z * param.z; }
+
+	float Len() const { return sqrt(x*x + y*y + z*z); }
+	float SquareLen() const { return x*x + y*y + z*z; }
+
+	/// Get as string with given separator
+	std::string Str(char sep = ',') const;
+	/// Get as string surrounded by parentheses with given separator
+	std::string PStr(char sep = ',') const;
+	/// Get as string with given separator with values rounded to ints
+	std::string DStr(char sep = ',') const;
+};
+
+Vector3D operator * (float f, Vector3D v);
+Vector3D operator / (float f, Vector3D v);
+Vector3D operator + (float f, Vector3D v);
+Vector3D operator - (float f, Vector3D v);

src/visual_tool.cpp

@@ -23,6 +23,7 @@
 #include "ass_dialogue.h"
 #include "ass_file.h"
 #include "ass_style.h"
+#include "auto4_base.h"
 #include "compat.h"
 #include "include/aegisub/context.h"
 #include "options.h"
@@ -475,6 +476,57 @@ void VisualToolBase::GetLineScale(AssDialogue *diag, Vector2D &scale) {
 	scale = Vector2D(x, y);
 }
 
+float VisualToolBase::GetLineFontSize(AssDialogue *diag) {
+	float fs = 0.f;
+
+	if (AssStyle *style = c->ass->GetStyle(diag->Style))
+		fs = style->fontsize;
+	auto blocks = diag->ParseTags();
+	if (param_vec tag = find_tag(blocks, "\\fs"))
+		fs = tag->front().Get(fs);
+
+	return fs;
+}
+
+int VisualToolBase::GetLineAlignment(AssDialogue *diag) {
+	int an = 0;
+
+	if (AssStyle *style = c->ass->GetStyle(diag->Style))
+		an = style->alignment;
+	auto blocks = diag->ParseTags();
+	if (param_vec tag = find_tag(blocks, "\\an"))
+		an = tag->front().Get(an);
+
+	return an;
+}
+
+void VisualToolBase::GetLineBaseExtents(AssDialogue *diag, double &width, double &height, double &descent, double &extlead) {
+	width = 0.;
+	height = 0.;
+	descent = 0.;
+	extlead = 0.;
+
+	AssStyle style;
+	if (AssStyle *basestyle = c->ass->GetStyle(diag->Style)) {
+		style = AssStyle(basestyle->GetEntryData());
+		style.scalex = 100.;
+		style.scaley = 100.;
+	}
+
+	auto blocks = diag->ParseTags();
+	if (param_vec tag = find_tag(blocks, "\\fs"))
+		style.fontsize = tag->front().Get(style.fontsize);
+	if (param_vec tag = find_tag(blocks, "\\fn"))
+		style.font = tag->front().Get(style.font);
+
+	std::string text = diag->GetStrippedText();
+	if (!Automation4::CalculateTextExtents(&style, text, width, height, descent, extlead)) {
+		// meh... let's make some ballpark estimates
+		width = style.fontsize * text.length();
+		height = style.fontsize;
+	}
+}
+
 void VisualToolBase::GetLineClip(AssDialogue *diag, Vector2D &p1, Vector2D &p2, bool &inverse) {
 	inverse = false;
 

src/visual_tool.h

@@ -128,6 +128,14 @@ protected:
 	void GetLineRotation(AssDialogue *diag, float &rx, float &ry, float &rz);
 	void GetLineShear(AssDialogue *diag, float& fax, float& fay);
 	void GetLineScale(AssDialogue *diag, Vector2D &scale);
+	float GetLineFontSize(AssDialogue *diag);
+	int GetLineAlignment(AssDialogue *diag);
+	/// @brief Compute text extents of the given line without any formatting
+	///
+	/// Formatting tags are stripped and \fs tags are respected, but \fscx and \fscy are kept as 100 even if
+	/// they are different in the style.
+	/// Returns a rough estimate when getting the precise extents fails
+	void GetLineBaseExtents(AssDialogue *diag, double &width, double &height, double &descent, double &extlead);
 	void GetLineClip(AssDialogue *diag, Vector2D &p1, Vector2D &p2, bool &inverse);
 	std::string GetLineVectorClip(AssDialogue *diag, int &scale, bool &inverse);
 

src/visual_tool_perspective.cpp

@@ -0,0 +1,271 @@
+// Copyright (c) 2022, arch1t3cht <arch1t3cht@gmail.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+/// @file visual_tool_perspective.cpp
+/// @brief 3D perspective visual typesetting tool
+/// @ingroup visual_ts
+
+#include "visual_tool_perspective.h"
+
+#include "compat.h"
+#include "include/aegisub/context.h"
+#include "options.h"
+#include "selection_controller.h"
+#include "vector3d.h"
+
+#include <libaegisub/format.h>
+
+#include <cmath>
+#include <wx/colour.h>
+
+static const float deg2rad = 3.1415926536f / 180.f;
+static const float rad2deg = 180.f / 3.1415926536f;
+static const float screen_z = 312.5;
+
+void VisualToolPerspective::Solve2x2Proper(float a11, float a12, float a21, float a22, float b1, float b2, float &x1, float &x2) {
+	// LU decomposition
+	// i = 1
+	a21 = a21 / a11;
+	// i = 2
+	a22 = a22 - a21 * a12;
+	// forward substitution
+	float z1 = b1;
+	float z2 = b2 - a21 * z1;
+	// backward substitution
+	x2 = z2 / a22;
+	x1 = (z1 - a12 * x2) / a11;
+}
+
+
+void VisualToolPerspective::Solve2x2(float a11, float a12, float a21, float a22, float b1, float b2, float &x1, float &x2) {
+	// Simple pivoting
+	if (abs(a11) >= abs(a21))
+		Solve2x2Proper(a11, a12, a21, a22, b1, b2, x1, x2);
+	else
+		Solve2x2Proper(a21, a22, a11, a12, b2, b1, x1, x2);
+}
+
+
+VisualToolPerspective::VisualToolPerspective(VideoDisplay *parent, agi::Context *context)
+: VisualTool<VisualDraggableFeature>(parent, context)
+{
+	orgf = new Feature;
+	orgf->type = DRAG_BIG_TRIANGLE;
+	features.push_back(*orgf);
+
+	for (int i = 0; i < 4; i++) {
+		quad_corners.push_back(new Feature);
+		old_positions.push_back(Vector2D());
+		quad_corners.back()->type = DRAG_SMALL_CIRCLE;
+		features.push_back(*quad_corners.back());
+	}
+}
+
+void VisualToolPerspective::Draw() {
+	if (!active_line) return;
+
+	wxColour line_color = to_wx(line_color_primary_opt->GetColor());
+	gl.SetLineColour(line_color);
+
+	for (int i = 0; i < 4; i++) {
+		gl.DrawDashedLine(quad_corners[i]->pos, quad_corners[(i + 1) % 4]->pos, 6);
+	}
+
+	DrawAllFeatures();
+}
+
+void VisualToolPerspective::UpdateDrag(Feature *feature) {
+	if (feature == orgf) {
+		Vector2D diff = orgf->pos - old_orgf;
+		for (int i = 0; i < 4; i++) {
+			quad_corners[i]->pos = quad_corners[i]->pos + diff;
+		}
+	}
+	Vector2D q1 = ToScriptCoords(quad_corners[0]->pos);
+	Vector2D q2 = ToScriptCoords(quad_corners[1]->pos);
+	Vector2D q3 = ToScriptCoords(quad_corners[2]->pos);
+	Vector2D q4 = ToScriptCoords(quad_corners[3]->pos);
+
+	Vector2D diag1 = q3 - q1;
+	Vector2D diag2 = q2 - q4;
+	Vector2D b = q4 - q1;
+	float center_la1, center_la2;
+	Solve2x2(diag1.X(), diag2.X(), diag1.Y(), diag2.Y(), b.X(), b.Y(), center_la1, center_la2);
+	if (center_la1 < 0 || center_la1 > 1 || -center_la2 < 0 || -center_la2 > 1) {
+		ResetFeaturePositions();
+		return;
+	}
+	Vector2D center = q1 + center_la1 * diag1;
+
+	// Normalize to center
+	q1 = q1 - center;
+	q2 = q2 - center;
+	q3 = q3 - center;
+	q4 = q4 - center;
+
+	// Find a parallelogram projecting to the quad
+	float z2, z4;
+	Vector2D side1 = q2 - q3;
+	Vector2D side2 = q4 - q3;
+	Solve2x2(side1.X(), side2.X(), side1.Y(), side2.Y(), -diag1.X(), -diag1.Y(), z2, z4);
+
+	float scalefactor = (z2 + z4) / 2;
+	Vector3D r1 = Vector3D(q1, screen_z) / scalefactor;
+	Vector3D r2 = z2 * Vector3D(q2, screen_z) / scalefactor;
+	Vector3D r4 = z4 * Vector3D(q4, screen_z) / scalefactor;
+
+	// Find the rotations
+	Vector3D n = (r2 - r1).Cross(r4 - r1);
+	float roty = atan(n.X() / n.Z());
+	n = n.RotateY(roty);
+	float rotx = atan(n.Y() / n.Z());
+
+	Vector3D ab = (r2 - r1).RotateY(roty).RotateX(rotx);
+	float rotz = atan(ab.Y() / ab.X());
+
+	Vector3D ad = (r4 - r1).RotateY(roty).RotateX(rotx).RotateZ(-rotz);
+	float fax = ad.X() / ad.Y();
+
+	float scalex = ab.Len() / textwidth;
+	float scaley = ad.Y() / textheight;
+
+	for (auto line : c->selectionController->GetSelectedSet()) {
+		angle_x = rotx * rad2deg;
+		angle_y = -roty * rad2deg;
+		angle_z = -rotz * rad2deg;
+		orgf->pos = FromScriptCoords(center);
+		SetOverride(line, "\\fax", agi::format("%.6f", fax * scaley / scalex));
+		SetOverride(line, "\\fay", agi::format("%.4f", 0)); 	// TODO just kill the tag
+		SetOverride(line, "\\fscx", agi::format("%.2f", 100 * scalex));
+		SetOverride(line, "\\fscy", agi::format("%.2f", 100 * scaley));
+		SetOverride(line, "\\frz", agi::format("%.4f", angle_z));
+		SetOverride(line, "\\frx", agi::format("%.4f", angle_x));
+		SetOverride(line, "\\fry", agi::format("%.4f", angle_y));
+		SetOverride(line, "\\pos", (center - Vector2D(fax_shift_factor * fax * scaley, 0)).PStr());
+		SetOverride(line, "\\org", center.PStr());
+	}
+	SaveFeaturePositions();
+}
+
+void VisualToolPerspective::ResetFeaturePositions() {
+	for (int i = 0; i < 4; i++) {
+		quad_corners[i]->pos = old_positions[i];
+	}
+	orgf->pos = old_orgf;
+}
+
+void VisualToolPerspective::SaveFeaturePositions() {
+	for (int i = 0; i < 4; i++) {
+		old_positions[i] = quad_corners[i]->pos;
+	}
+	old_orgf = orgf->pos;
+}
+
+void VisualToolPerspective::SetFeaturePositions() {
+	double textleft, texttop = 0.;
+
+	switch ((align - 1) % 3) {
+		case 1:
+			textleft = -textwidth / 2;
+			break;
+		case 2:
+			textleft = -textwidth;
+			break;
+		default:
+			break;
+	}
+	switch ((align - 1) / 3) {
+		case 0:
+			texttop = -textheight;
+			break;
+		case 1:
+			texttop = -textheight / 2;
+			break;
+		default:
+			break;
+	}
+
+	Vector2D textrect[] = {
+		Vector2D(0, 0),
+		Vector2D(textwidth, 0),
+		Vector2D(textwidth, textheight),
+		Vector2D(0, textheight),
+	};
+
+	for (int i = 0; i < 4; i++) {
+		Vector2D p = textrect[i];
+		// Apply \fax and \fay
+		p = Vector2D(p.X() + p.Y() * fax, p.X() * fay + p.Y());
+		// Translate to alignment point
+		p = p + Vector2D(textleft, texttop);
+		// Apply scaling
+		p = Vector2D(p.X() * fsc.X() / 100., p.Y() * fsc.Y() / 100.);
+		// Translate relative to origin
+		p = p + pos - org;
+		// Rotate ZXY
+		Vector3D q(p);
+		q = q.RotateZ(-angle_z * deg2rad);
+		q = q.RotateX(-angle_x * deg2rad);
+		q = q.RotateY(angle_y * deg2rad);
+		// Project
+		q = (screen_z / (q.Z() + screen_z)) * q;
+		// Move to origin
+		Vector2D r = q.XY() + org;
+
+		quad_corners[i]->pos = FromScriptCoords(r);
+	}
+
+	if (!(orgf->pos = org))
+		orgf->pos = pos;
+	orgf->pos = FromScriptCoords(orgf->pos);
+	SaveFeaturePositions();
+}
+
+void VisualToolPerspective::DoRefresh() {
+	if (!active_line) return;
+
+	org = GetLineOrigin(active_line);
+	pos = GetLinePosition(active_line);
+	if (!org)
+		org = pos;
+
+	GetLineRotation(active_line, angle_x, angle_y, angle_z);
+	GetLineShear(active_line, fax, fay);
+	GetLineScale(active_line, fsc);
+
+	float fs = GetLineFontSize(active_line);
+	align = GetLineAlignment(active_line);
+
+	switch (align) {
+		case 1:
+		case 2:
+		case 3:
+			fax_shift_factor = fs;
+			break;
+		case 4:
+		case 5:
+		case 6:
+			fax_shift_factor = fs / 2;
+			break;
+		default:
+			fax_shift_factor = 0.;
+			break;
+	}
+
+	double descend, extlead;
+	GetLineBaseExtents(active_line, textwidth, textheight, descend, extlead);
+	SetFeaturePositions();
+}

src/visual_tool_perspective.h

@@ -0,0 +1,61 @@
+// Copyright (c) 2022, arch1t3cht <arch1t3cht@gmail.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+/// @file visual_tool_perspective.h
+/// @see visual_tool_perspective.cpp
+/// @ingroup visual_ts
+///
+
+#include "visual_feature.h"
+#include "visual_tool.h"
+
+class VisualToolPerspective final : public VisualTool<VisualDraggableFeature> {
+	float angle_x = 0.f; /// Current x rotation
+	float angle_y = 0.f; /// Current y rotation
+	float angle_z = 0.f; /// Current z rotation
+
+	float fax = 0.f;
+	float fay = 0.f;
+
+	int align = 0;
+	float fax_shift_factor = 0.f;
+
+	double textwidth = 0.f;
+	double textheight = 0.f;
+
+	Vector2D fsc;
+
+	Vector2D org;
+	Vector2D pos;
+
+	Feature *orgf;
+	Vector2D old_orgf;
+
+	std::vector<Vector2D> old_positions;
+	std::vector<Feature *> quad_corners;
+
+	void Solve2x2Proper(float a11, float a12, float a21, float a22, float b1, float b2, float &x1, float &x2);
+	void Solve2x2(float a11, float a12, float a21, float a22, float b1, float b2, float &x1, float &x2);
+
+	void DoRefresh() override;
+	void Draw() override;
+	void UpdateDrag(Feature *feature) override;
+	void SetFeaturePositions();
+	void ResetFeaturePositions();
+	void SaveFeaturePositions();
+public:
+	VisualToolPerspective(VideoDisplay *parent, agi::Context *context);
+};