From 7e2d4a6bf96add175c4f03f7e86bf5fc288670f8 Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Fri, 15 Mar 2019 01:11:57 -0400
Subject: [PATCH] Use larger canvas for RackScrollWidget.

---
 helper.py                        |  5 +--
 include/app/RackScrollWidget.hpp |  1 +
 include/app/common.hpp           |  1 +
 include/math.hpp                 | 73 ++++++++++++++++----------------
 src/app/RackRail.cpp             |  9 ----
 src/app/RackScrollWidget.cpp     | 45 ++++++++++++--------
 src/app/RackWidget.cpp           | 24 ++++-------
 src/engine/Engine.cpp            | 14 +++---
 src/patch.cpp                    |  4 +-
 src/ui/ScrollWidget.cpp          | 25 +++++------
 10 files changed, 96 insertions(+), 105 deletions(-)

diff --git a/helper.py b/helper.py
index dca11501..5ddf2a44 100755
--- a/helper.py
+++ b/helper.py
@@ -7,9 +7,8 @@ import json
 import xml.etree.ElementTree
 
 
-if sys.version_info < (3, 6):
-	print("Python 3.6 or higher required")
-	exit(1)
+# Version check
+f"Python 3.6 is required"
 
 
 class UserException(Exception):
diff --git a/include/app/RackScrollWidget.hpp b/include/app/RackScrollWidget.hpp
index 14ed7b44..8a344c5e 100644
--- a/include/app/RackScrollWidget.hpp
+++ b/include/app/RackScrollWidget.hpp
@@ -20,6 +20,7 @@ struct RackScrollWidget : ui::ScrollWidget {
 	void draw(const DrawArgs &args) override;
 	void onHover(const widget::HoverEvent &e) override;
 	void onHoverScroll(const widget::HoverScrollEvent &e) override;
+	void reset();
 };
 
 
diff --git a/include/app/common.hpp b/include/app/common.hpp
index c76083ab..0dbd70a9 100644
--- a/include/app/common.hpp
+++ b/include/app/common.hpp
@@ -43,6 +43,7 @@ inline math::Vec mm2px(math::Vec mm) {
 static const float RACK_GRID_WIDTH = 15;
 static const float RACK_GRID_HEIGHT = 380;
 static const math::Vec RACK_GRID_SIZE = math::Vec(RACK_GRID_WIDTH, RACK_GRID_HEIGHT);
+static const math::Vec RACK_OFFSET = RACK_GRID_SIZE.mult(math::Vec(2000, 100));
 
 
 } // namespace app
diff --git a/include/math.hpp b/include/math.hpp
index 9cb7cd7f..ba44e13f 100644
--- a/include/math.hpp
+++ b/include/math.hpp
@@ -15,25 +15,25 @@ namespace math {
 // basic integer functions
 ////////////////////
 
-/** Returns true if x is odd */
+/** Returns true if x is odd. */
 inline bool isEven(int x) {
 	return x % 2 == 0;
 }
 
-/** Returns true if x is odd */
+/** Returns true if x is odd. */
 inline bool isOdd(int x) {
 	return x % 2 != 0;
 }
 
-/** Limits `x` between `a` and `b`
-Assumes a <= b
+/** Limits `x` between `a` and `b`.
+If b < a, returns a.
 */
 inline int clamp(int x, int a, int b) {
-	return std::min(std::max(x, a), b);
+	return std::max(std::min(x, b), a);
 }
 
-/** Limits `x` between `a` and `b`
-If a > b, switches the two values
+/** Limits `x` between `a` and `b`.
+If b < a, switches the two values.
 */
 inline int clampSafe(int x, int a, int b) {
 	return clamp(x, std::min(a, b), std::max(a, b));
@@ -72,8 +72,7 @@ inline void eucDivMod(int a, int b, int *div, int *mod) {
 	}
 }
 
-/** Returns floor(log_2(n)), or 0 if n == 1.
-*/
+/** Returns floor(log_2(n)), or 0 if n == 1. */
 inline int log2(int n) {
 	int i = 0;
 	while (n >>= 1) {
@@ -82,7 +81,7 @@ inline int log2(int n) {
 	return i;
 }
 
-/** Returns whether `n` is a power of 2 */
+/** Returns whether `n` is a power of 2. */
 inline bool isPow2(int n) {
 	return n > 0 && (n & (n - 1)) == 0;
 }
@@ -91,22 +90,22 @@ inline bool isPow2(int n) {
 // basic float functions
 ////////////////////
 
-/** Limits `x` between `a` and `b`
-Assumes a <= b
+/** Limits `x` between `a` and `b`.
+If b < a, returns a.
 */
 inline float clamp(float x, float a, float b) {
-	return std::fmin(std::fmax(x, a), b);
+	return std::fmax(std::fmin(x, b), a);
 }
 
-/** Limits `x` between `a` and `b`
-If a > b, switches the two values
+/** Limits `x` between `a` and `b`.
+If b < a, switches the two values.
 */
 inline float clampSafe(float x, float a, float b) {
 	return clamp(x, std::fmin(a, b), std::fmax(a, b));
 }
 
-/** Returns 1 for positive numbers, -1 for negative numbers, and 0 for zero
-See https://en.wikipedia.org/wiki/Sign_function
+/** Returns 1 for positive numbers, -1 for negative numbers, and 0 for zero.
+See https://en.wikipedia.org/wiki/Sign_function.
 */
 inline float sgn(float x) {
 	return x > 0.f ? 1.f : x < 0.f ? -1.f : 0.f;
@@ -118,18 +117,19 @@ inline float normalizeZero(float x) {
 }
 
 /** Euclidean modulus. Always returns 0 <= mod < b.
-See https://en.wikipedia.org/wiki/Euclidean_division
+See https://en.wikipedia.org/wiki/Euclidean_division.
 */
 inline float eucMod(float a, float base) {
 	float mod = std::fmod(a, base);
 	return (mod >= 0.f) ? mod : mod + base;
 }
 
+/** Returns whether a is within epsilon distance from b. */
 inline bool isNear(float a, float b, float epsilon = 1e-6f) {
 	return std::fabs(a - b) <= epsilon;
 }
 
-/** If the magnitude of x if less than epsilon, return 0 */
+/** If the magnitude of x if less than epsilon, return 0. */
 inline float chop(float x, float epsilon = 1e-6f) {
 	return isNear(x, 0.f, epsilon) ? 0.f : x;
 }
@@ -142,7 +142,7 @@ inline float crossfade(float a, float b, float p) {
 	return a + (b - a) * p;
 }
 
-/** Linearly interpolate an array `p` with index `x`
+/** Linearly interpolates an array `p` with index `x`.
 Assumes that the array at `p` is of length at least floor(x)+1.
 */
 inline float interpolateLinear(const float *p, float x) {
@@ -151,8 +151,8 @@ inline float interpolateLinear(const float *p, float x) {
 	return crossfade(p[xi], p[xi+1], xf);
 }
 
-/** Complex multiply c = a * b
-Arguments may be the same pointers
+/** Complex multiplies c = a * b.
+Arguments may be the same pointers.
 i.e. cmultf(&ar, &ai, ar, ai, br, bi)
 */
 inline void complexMult(float *cr, float *ci, float ar, float ai, float br, float bi) {
@@ -173,7 +173,7 @@ struct Vec {
 	Vec() {}
 	Vec(float x, float y) : x(x), y(y) {}
 
-	/** Negates the vector
+	/** Negates the vector.
 	Equivalent to a reflection across the y=-x line.
 	*/
 	Vec neg() const {
@@ -206,13 +206,13 @@ struct Vec {
 	float square() const {
 		return x * x + y * y;
 	}
-	/** Rotates counterclockwise in radians */
+	/** Rotates counterclockwise in radians. */
 	Vec rotate(float angle) {
 		float sin = std::sin(angle);
 		float cos = std::cos(angle);
 		return Vec(x * cos - y * sin, x * sin + y * cos);
 	}
-	/** Swaps the coordinates
+	/** Swaps the coordinates.
 	Equivalent to a reflection across the y=x line.
 	*/
 	Vec flip() const {
@@ -256,22 +256,23 @@ struct Rect {
 
 	Rect() {}
 	Rect(Vec pos, Vec size) : pos(pos), size(size) {}
-	/** Constructs a Rect from the upper-left position `a` and lower-right pos `b` */
+	Rect(float posX, float posY, float sizeX, float sizeY) : pos(math::Vec(posX, posY)), size(math::Vec(sizeX, sizeY)) {}
+	/** Constructs a Rect from the upper-left position `a` and lower-right pos `b`. */
 	static Rect fromMinMax(Vec a, Vec b) {
 		return Rect(a, b.minus(a));
 	}
 
-	/** Returns whether this Rect contains an entire point, inclusive on the top/left, non-inclusive on the bottom/right */
+	/** Returns whether this Rect contains an entire point, inclusive on the top/left, non-inclusive on the bottom/right. */
 	bool isContaining(Vec v) const {
 		return pos.x <= v.x && v.x < pos.x + size.x
 			&& pos.y <= v.y && v.y < pos.y + size.y;
 	}
-	/** Returns whether this Rect contains an entire Rect */
+	/** Returns whether this Rect contains an entire Rect. */
 	bool isContaining(Rect r) const {
 		return pos.x <= r.pos.x && r.pos.x + r.size.x <= pos.x + size.x
 			&& pos.y <= r.pos.y && r.pos.y + r.size.y <= pos.y + size.y;
 	}
-	/** Returns whether this Rect overlaps with another Rect */
+	/** Returns whether this Rect overlaps with another Rect. */
 	bool isIntersecting(Rect r) const {
 		return (pos.x + size.x > r.pos.x && r.pos.x + r.size.x > pos.x)
 			&& (pos.y + size.y > r.pos.y && r.pos.y + r.size.y > pos.y);
@@ -300,7 +301,7 @@ struct Rect {
 	Vec getBottomRight() const {
 		return pos.plus(size);
 	}
-	/** Clamps the edges of the rectangle to fit within a bound */
+	/** Clamps the edges of the rectangle to fit within a bound. */
 	Rect clamp(Rect bound) const {
 		Rect r;
 		r.pos.x = math::clampSafe(pos.x, bound.pos.x, bound.pos.x + bound.size.x);
@@ -309,7 +310,7 @@ struct Rect {
 		r.size.y = math::clamp(pos.y + size.y, bound.pos.y, bound.pos.y + bound.size.y) - r.pos.y;
 		return r;
 	}
-	/** Nudges the position to fix inside a bounding box */
+	/** Nudges the position to fix inside a bounding box. */
 	Rect nudge(Rect bound) const {
 		Rect r;
 		r.size = size;
@@ -317,7 +318,7 @@ struct Rect {
 		r.pos.y = math::clampSafe(pos.y, bound.pos.y, bound.pos.y + bound.size.y - size.y);
 		return r;
 	}
-	/** Expands this Rect to contain `b` */
+	/** Expands this Rect to contain `b`. */
 	Rect expand(Rect b) const {
 		Rect r;
 		r.pos.x = std::fmin(pos.x, b.pos.x);
@@ -326,7 +327,7 @@ struct Rect {
 		r.size.y = std::fmax(pos.y + size.y, b.pos.y + b.size.y) - r.pos.y;
 		return r;
 	}
-	/** Returns the intersection of `this` and `b` */
+	/** Returns the intersection of `this` and `b`. */
 	Rect intersect(Rect b) const {
 		Rect r;
 		r.pos.x = std::fmax(pos.x, b.pos.x);
@@ -335,11 +336,11 @@ struct Rect {
 		r.size.y = std::fmin(pos.y + size.y, b.pos.y + b.size.y) - r.pos.y;
 		return r;
 	}
-	/** Returns a Rect with its position set to zero */
+	/** Returns a Rect with its position set to zero. */
 	Rect zeroPos() const {
 		return Rect(Vec(), size);
 	}
-	/** Expands each corner
+	/** Expands each corner.
 	Use a negative delta to shrink.
 	*/
 	Rect grow(Vec delta) const {
@@ -371,7 +372,7 @@ inline Vec Vec::clampSafe(Rect bound) const {
 /** Expands a Vec and Rect into a comma-separated list.
 Useful for print debugging.
 
-	printf("%f %f %f %f", RECT_ARGS(r));
+	printf("(%f %f) (%f %f %f %f)", VEC_ARGS(v), RECT_ARGS(r));
 
 Or passing the values to a C function.
 
diff --git a/src/app/RackRail.cpp b/src/app/RackRail.cpp
index 13e251e1..ae522eef 100644
--- a/src/app/RackRail.cpp
+++ b/src/app/RackRail.cpp
@@ -47,15 +47,6 @@ void RackRail::draw(const DrawArgs &args) {
 		nvgLineTo(args.vg, box.size.x, railY + RACK_GRID_HEIGHT - 0.5);
 		nvgStroke(args.vg);
 	}
-
-
-	// Useful for screenshots
-	if (0) {
-		nvgBeginPath(args.vg);
-		nvgRect(args.vg, 0.0, 0.0, box.size.x, box.size.y);
-		nvgFillColor(args.vg, nvgRGBf(1.0, 1.0, 1.0));
-		nvgFill(args.vg);
-	}
 }
 
 
diff --git a/src/app/RackScrollWidget.cpp b/src/app/RackScrollWidget.cpp
index 768a2e0e..53439524 100644
--- a/src/app/RackScrollWidget.cpp
+++ b/src/app/RackScrollWidget.cpp
@@ -14,11 +14,14 @@ RackScrollWidget::RackScrollWidget() {
 	container->addChild(zoomWidget);
 
 	rackWidget = new RackWidget;
+	rackWidget->box.size = RACK_OFFSET.mult(2);
 	zoomWidget->addChild(rackWidget);
+
+	reset();
 }
 
 void RackScrollWidget::step() {
-	float zoom = std::round(settings.zoom * 100) / 100;
+	float zoom = std::round(settings.zoom / 0.01) * 0.01;
 	if (zoom != zoomWidget->zoom) {
 		// Set offset based on zoomPos
 		offset = offset.plus(zoomPos).div(zoomWidget->zoom).mult(zoom).minus(zoomPos);
@@ -28,14 +31,20 @@ void RackScrollWidget::step() {
 
 	zoomPos = box.size.div(2);
 
-	// Resize RackWidget to be a bit larger than the viewport
-	rackWidget->box.size = box.size
-		.minus(container->box.pos)
-		.plus(math::Vec(500, 500))
-		.div(zoomWidget->zoom);
-
-	// Resize ZoomWidget
-	zoomWidget->box.size = rackWidget->box.size.mult(zoomWidget->zoom);
+	// Set zoomWidget box to module bounding box
+	math::Rect moduleBox = rackWidget->moduleContainer->getChildrenBoundingBox();
+	if (!moduleBox.size.isFinite())
+		moduleBox = math::Rect(RACK_OFFSET, math::Vec(0, 0));
+	zoomWidget->box.pos = moduleBox.pos.mult(zoomWidget->zoom);
+	zoomWidget->box.size = moduleBox.size.mult(zoomWidget->zoom);
+	// Expand to viewport
+	math::Rect viewportBox = box;
+	viewportBox.pos = viewportBox.pos.plus(offset);
+	zoomWidget->box = zoomWidget->box.expand(viewportBox);
+	// Grow a few pixels
+	zoomWidget->box = zoomWidget->box.grow(math::Vec(100, 100));
+	// Reposition rackWidget
+	rackWidget->box.pos = zoomWidget->box.pos.div(zoomWidget->zoom).neg();
 
 	// Scroll rack if dragging cable near the edge of the screen
 	math::Vec pos = APP->window->mousePos;
@@ -58,6 +67,7 @@ void RackScrollWidget::step() {
 
 
 void RackScrollWidget::draw(const DrawArgs &args) {
+	// DEBUG("%f %f %f %f", RECT_ARGS(args.clipBox));
 	ScrollWidget::draw(args);
 }
 
@@ -72,18 +82,14 @@ void RackScrollWidget::onHover(const widget::HoverEvent &e) {
 		else if ((APP->window->getMods() & WINDOW_MOD_MASK) == GLFW_MOD_SHIFT)
 			arrowSpeed /= 4.0;
 
-		if (glfwGetKey(APP->window->win, GLFW_KEY_LEFT) == GLFW_PRESS) {
+		if (glfwGetKey(APP->window->win, GLFW_KEY_LEFT) == GLFW_PRESS)
 			offset.x -= arrowSpeed;
-		}
-		if (glfwGetKey(APP->window->win, GLFW_KEY_RIGHT) == GLFW_PRESS) {
+		if (glfwGetKey(APP->window->win, GLFW_KEY_RIGHT) == GLFW_PRESS)
 			offset.x += arrowSpeed;
-		}
-		if (glfwGetKey(APP->window->win, GLFW_KEY_UP) == GLFW_PRESS) {
+		if (glfwGetKey(APP->window->win, GLFW_KEY_UP) == GLFW_PRESS)
 			offset.y -= arrowSpeed;
-		}
-		if (glfwGetKey(APP->window->win, GLFW_KEY_DOWN) == GLFW_PRESS) {
+		if (glfwGetKey(APP->window->win, GLFW_KEY_DOWN) == GLFW_PRESS)
 			offset.y += arrowSpeed;
-		}
 	}
 
 	ScrollWidget::onHover(e);
@@ -105,6 +111,11 @@ void RackScrollWidget::onHoverScroll(const widget::HoverScrollEvent &e) {
 	ScrollWidget::onHoverScroll(e);
 }
 
+void RackScrollWidget::reset() {
+	offset = RACK_OFFSET.mult(zoomWidget->zoom);
+	offset = offset.minus(math::Vec(20, 20));
+}
+
 
 } // namespace app
 } // namespace rack
diff --git a/src/app/RackWidget.cpp b/src/app/RackWidget.cpp
index a509e21a..6ecba782 100644
--- a/src/app/RackWidget.cpp
+++ b/src/app/RackWidget.cpp
@@ -97,13 +97,7 @@ RackWidget::~RackWidget() {
 }
 
 void RackWidget::step() {
-	// Expand size to fit modules
-	math::Vec moduleSize = moduleContainer->getChildrenBoundingBox().getBottomRight();
-	// We assume that the size is reset by a parent before calling step(). Otherwise it will grow unbounded.
-	box.size = box.size.max(moduleSize);
-
 	// Adjust size and position of rails
-	widget::Widget *rail = rails->children.front();
 	math::Rect bound = getViewport(math::Rect(math::Vec(), box.size));
 	if (!rails->box.isContaining(bound)) {
 		math::Vec cellMargin = math::Vec(20, 1);
@@ -111,14 +105,15 @@ void RackWidget::step() {
 		rails->box.size = bound.size.plus(cellMargin.mult(RACK_GRID_SIZE).mult(2));
 		rails->dirty = true;
 
+		RackRail *rail = rails->getFirstDescendantOfType<RackRail>();
 		rail->box.size = rails->box.size;
 	}
 
-	Widget::step();
+	OpaqueWidget::step();
 }
 
 void RackWidget::draw(const DrawArgs &args) {
-	Widget::draw(args);
+	OpaqueWidget::draw(args);
 }
 
 void RackWidget::onHover(const widget::HoverEvent &e) {
@@ -157,7 +152,6 @@ void RackWidget::onButton(const widget::ButtonEvent &e) {
 }
 
 void RackWidget::onZoom(const widget::ZoomEvent &e) {
-	rails->box.size = math::Vec();
 	OpaqueWidget::onZoom(e);
 }
 
@@ -189,7 +183,8 @@ json_t *RackWidget::toJson() {
 			// id
 			json_object_set_new(moduleJ, "id", json_integer(moduleWidget->module->id));
 			// pos
-			math::Vec pos = moduleWidget->box.pos.div(RACK_GRID_SIZE).round();
+			math::Vec pos = moduleWidget->box.pos.minus(RACK_OFFSET);
+			pos = pos.div(RACK_GRID_SIZE).round();
 			json_t *posJ = json_pack("[i, i]", (int) pos.x, (int) pos.y);
 			json_object_set_new(moduleJ, "pos", posJ);
 		}
@@ -252,6 +247,7 @@ void RackWidget::fromJson(json_t *rootJ) {
 			else {
 				moduleWidget->box.pos = pos.mult(RACK_GRID_SIZE);
 			}
+			moduleWidget->box.pos = moduleWidget->box.pos.plus(RACK_OFFSET);
 
 			addModule(moduleWidget);
 		}
@@ -387,10 +383,6 @@ void RackWidget::removeModule(ModuleWidget *m) {
 }
 
 bool RackWidget::requestModuleBox(ModuleWidget *m, math::Rect requestedBox) {
-	// Check bounds
-	if (requestedBox.pos.x < 0 || requestedBox.pos.y < 0)
-		return false;
-
 	// Check intersection with other modules
 	for (widget::Widget *m2 : moduleContainer->children) {
 		// Don't intersect with self
@@ -412,8 +404,8 @@ bool RackWidget::requestModuleBoxNearest(ModuleWidget *m, math::Rect requestedBo
 	int x0 = std::round(requestedBox.pos.x / RACK_GRID_WIDTH);
 	int y0 = std::round(requestedBox.pos.y / RACK_GRID_HEIGHT);
 	std::vector<math::Vec> positions;
-	for (int y = std::max(0, y0 - 8); y < y0 + 8; y++) {
-		for (int x = std::max(0, x0 - 400); x < x0 + 400; x++) {
+	for (int y = y0 - 4; y < y0 + 4; y++) {
+		for (int x = x0 - 200; x < x0 + 200; x++) {
 			positions.push_back(math::Vec(x * RACK_GRID_WIDTH, y * RACK_GRID_HEIGHT));
 		}
 	}
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 91630e37..28d6768f 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -473,14 +473,14 @@ void Engine::removeModule(Module *module) {
 			paramHandle->module = NULL;
 	}
 	// Update adjacent modules
-	for (Module *module : internal->modules) {
-		if (module->leftModule == module) {
-			module->leftModuleId = -1;
-			module->leftModule = NULL;
+	for (Module *m : internal->modules) {
+		if (m->leftModule == module) {
+			m->leftModuleId = -1;
+			m->leftModule = NULL;
 		}
-		if (module->rightModule == module) {
-			module->rightModuleId = -1;
-			module->rightModule = NULL;
+		if (m->rightModule == module) {
+			m->rightModuleId = -1;
+			m->rightModule = NULL;
 		}
 	}
 	// Check that the module actually exists
diff --git a/src/patch.cpp b/src/patch.cpp
index 8e045651..1fdcbcd5 100644
--- a/src/patch.cpp
+++ b/src/patch.cpp
@@ -60,7 +60,7 @@ void PatchManager::init(std::string path) {
 void PatchManager::reset() {
 	APP->history->clear();
 	APP->scene->rack->clear();
-	APP->scene->rackScroll->offset = math::Vec(0, 0);
+	APP->scene->rackScroll->reset();
 	// Fails silently if file does not exist
 	load(asset::user("template.vcv"));
 	legacy = 0;
@@ -169,7 +169,7 @@ bool PatchManager::load(std::string path) {
 
 	APP->history->clear();
 	APP->scene->rack->clear();
-	APP->scene->rackScroll->offset = math::Vec(0, 0);
+	APP->scene->rackScroll->reset();
 	fromJson(rootJ);
 	return true;
 }
diff --git a/src/ui/ScrollWidget.cpp b/src/ui/ScrollWidget.cpp
index 58a6f2a0..1cbdecf8 100644
--- a/src/ui/ScrollWidget.cpp
+++ b/src/ui/ScrollWidget.cpp
@@ -37,22 +37,17 @@ void ScrollWidget::step() {
 	Widget::step();
 
 	// Clamp scroll offset
-	math::Vec containerCorner = container->getChildrenBoundingBox().getBottomRight();
-	math::Rect containerBox = math::Rect(math::Vec(0, 0), containerCorner.minus(box.size));
-	offset = offset.clamp(containerBox);
-	// Lock offset to top/left if no scrollbar will display
-	if (containerBox.size.x < 0.0)
-		offset.x = 0.0;
-	if (containerBox.size.y < 0.0)
-		offset.y = 0.0;
-
-	// Update the container's positions from the offset
+	math::Rect containerBox = container->getChildrenBoundingBox();
+	math::Rect offsetBounds = containerBox;
+	offsetBounds.size = offsetBounds.size.minus(box.size);
+	offset = offset.clamp(offsetBounds);
+
+	// Update the container's position from the offset
 	container->box.pos = offset.neg().round();
 
 	// Update scrollbar offsets and sizes
-	math::Vec viewportSize = container->getChildrenBoundingBox().getBottomRight();
-	math::Vec scrollbarOffset = offset.div(viewportSize.minus(box.size));
-	math::Vec scrollbarSize = box.size.div(viewportSize);
+	math::Vec scrollbarOffset = offset.minus(containerBox.pos).div(offsetBounds.size);
+	math::Vec scrollbarSize = box.size.div(containerBox.size);
 
 	horizontalScrollBar->visible = (0.0 < scrollbarSize.x && scrollbarSize.x < 1.0);
 	verticalScrollBar->visible = (0.0 < scrollbarSize.y && scrollbarSize.y < 1.0);
@@ -61,8 +56,8 @@ void ScrollWidget::step() {
 	horizontalScrollBar->size = scrollbarSize.x;
 	verticalScrollBar->size = scrollbarSize.y;
 
-	// Resize scroll bars
-	math::Vec inner = math::Vec(box.size.x - verticalScrollBar->box.size.x, box.size.y - horizontalScrollBar->box.size.y);
+	// Reposition and resize scroll bars
+	math::Vec inner = box.size.minus(math::Vec(verticalScrollBar->box.size.x, horizontalScrollBar->box.size.y));
 	horizontalScrollBar->box.pos.y = inner.y;
 	verticalScrollBar->box.pos.x = inner.x;
 	horizontalScrollBar->box.size.x = verticalScrollBar->visible ? inner.x : box.size.x;