obs-studio/frontend/components/Multiview.cpp

#include "Multiview.hpp"

#include <utility/display-helpers.hpp>
#include <widgets/OBSBasic.hpp>

#include <obs-frontend-api.h>

Multiview::Multiview()
{
	InitSafeAreas(&actionSafeMargin, &graphicsSafeMargin, &fourByThreeSafeMargin, &leftLine, &topLine, &rightLine);
}

Multiview::~Multiview()
{
	for (OBSWeakSource &weakSrc : multiviewScenes) {
		OBSSource src = OBSGetStrongRef(weakSrc);
		if (src)
			obs_source_dec_showing(src);
	}

	obs_enter_graphics();
	gs_vertexbuffer_destroy(actionSafeMargin);
	gs_vertexbuffer_destroy(graphicsSafeMargin);
	gs_vertexbuffer_destroy(fourByThreeSafeMargin);
	gs_vertexbuffer_destroy(leftLine);
	gs_vertexbuffer_destroy(topLine);
	gs_vertexbuffer_destroy(rightLine);
	obs_leave_graphics();
}

static OBSSource CreateLabel(const char *name, size_t h)
{
	OBSDataAutoRelease settings = obs_data_create();
	OBSDataAutoRelease font = obs_data_create();

	std::string text;
	text += " ";
	text += name;
	text += " ";

#if defined(_WIN32)
	obs_data_set_string(font, "face", "Arial");
#elif defined(__APPLE__)
	obs_data_set_string(font, "face", "Helvetica");
#else
	obs_data_set_string(font, "face", "Monospace");
#endif
	obs_data_set_int(font, "flags", 1); // Bold text
	obs_data_set_int(font, "size", int(h / 9.81));

	obs_data_set_obj(settings, "font", font);
	obs_data_set_string(settings, "text", text.c_str());
	obs_data_set_bool(settings, "outline", false);
	obs_data_set_int(settings, "opacity", 50);

#ifdef _WIN32
	const char *text_source_id = "text_gdiplus";
#else
	const char *text_source_id = "text_ft2_source";
#endif

	OBSSourceAutoRelease txtSource = obs_source_create_private(text_source_id, name, settings);

	return txtSource.Get();
}

void Multiview::Update(MultiviewLayout multiviewLayout, bool drawLabel, bool drawSafeArea)
{
	this->multiviewLayout = multiviewLayout;
	this->drawLabel = drawLabel;
	this->drawSafeArea = drawSafeArea;

	struct obs_video_info ovi;
	obs_get_video_info(&ovi);

	uint32_t w = ovi.base_width;
	uint32_t h = ovi.base_height;
	fw = float(w);
	fh = float(h);
	ratio = fw / fh;

	struct obs_frontend_source_list scenes = {};
	obs_frontend_get_scenes(&scenes);

	switch (multiviewLayout) {
	case MultiviewLayout::HORIZONTAL_TOP_18_SCENES:
		pvwprgCX = fw / 2;
		pvwprgCY = fh / 2;

		maxSrcs = 18;
		break;
	case MultiviewLayout::HORIZONTAL_TOP_24_SCENES:
		pvwprgCX = fw / 3;
		pvwprgCY = fh / 3;

		maxSrcs = 24;
		break;
	case MultiviewLayout::SCENES_ONLY_4_SCENES:
		pvwprgCX = fw / 2;
		pvwprgCY = fh / 2;
		maxSrcs = 4;
		break;
	case MultiviewLayout::SCENES_ONLY_9_SCENES:
		pvwprgCX = fw / 3;
		pvwprgCY = fh / 3;
		maxSrcs = 9;
		break;
	case MultiviewLayout::SCENES_ONLY_16_SCENES:
		pvwprgCX = fw / 4;
		pvwprgCY = fh / 4;
		maxSrcs = 16;
		break;
	case MultiviewLayout::SCENES_ONLY_25_SCENES:
		pvwprgCX = fw / 5;
		pvwprgCY = fh / 5;
		maxSrcs = 25;
		break;
	default:
		pvwprgCX = fw / 2;
		pvwprgCY = fh / 2;

		maxSrcs = 8;
	}

	ppiCX = pvwprgCX - thicknessx2;
	ppiCY = pvwprgCY - thicknessx2;
	ppiScaleX = (pvwprgCX - thicknessx2) / fw;
	ppiScaleY = (pvwprgCY - thicknessx2) / fh;

	switch (multiviewLayout) {
	case MultiviewLayout::HORIZONTAL_TOP_18_SCENES:
		scenesCX = pvwprgCX / 3;
		scenesCY = pvwprgCY / 3;
		break;
	case MultiviewLayout::SCENES_ONLY_4_SCENES:
	case MultiviewLayout::SCENES_ONLY_9_SCENES:
	case MultiviewLayout::SCENES_ONLY_16_SCENES:
	case MultiviewLayout::SCENES_ONLY_25_SCENES:
		scenesCX = pvwprgCX;
		scenesCY = pvwprgCY;
		break;
	default:
		scenesCX = pvwprgCX / 2;
		scenesCY = pvwprgCY / 2;
	}

	siCX = scenesCX - thicknessx2;
	siCY = scenesCY - thicknessx2;
	siScaleX = (scenesCX - thicknessx2) / fw;
	siScaleY = (scenesCY - thicknessx2) / fh;

	std::vector<OBSWeakSource> updatedScenes;
	std::vector<OBSSource> updatedLabels;

	updatedLabels.emplace_back(CreateLabel(Str("StudioMode.Preview"), h / 2));
	updatedLabels.emplace_back(CreateLabel(Str("StudioMode.Program"), h / 2));

	size_t i = 0;
	while (i < scenes.sources.num && updatedScenes.size() < maxSrcs) {
		obs_source_t *src = scenes.sources.array[i++];
		OBSDataAutoRelease data = obs_source_get_private_settings(src);

		obs_data_set_default_bool(data, "show_in_multiview", true);
		if (!obs_data_get_bool(data, "show_in_multiview"))
			continue;

		updatedScenes.emplace_back(OBSGetWeakRef(src));
		obs_source_inc_showing(src);

		updatedLabels.emplace_back(CreateLabel(obs_source_get_name(src), h / 3));
	}

	obs_frontend_source_list_free(&scenes);

	for (OBSWeakSource &weakSrc : multiviewScenes) {
		OBSSource src = OBSGetStrongRef(weakSrc);
		if (src)
			obs_source_dec_showing(src);
	}

	multiviewScenes = std::move(updatedScenes);
	multiviewLabels = std::move(updatedLabels);
}

static inline uint32_t labelOffset(MultiviewLayout multiviewLayout, obs_source_t *label, uint32_t cx)
{
	uint32_t w = obs_source_get_width(label);

	int n; // Twice of scale factor of preview and program scenes
	switch (multiviewLayout) {
	case MultiviewLayout::HORIZONTAL_TOP_24_SCENES:
		n = 6;
		break;
	case MultiviewLayout::SCENES_ONLY_25_SCENES:
		n = 10;
		break;
	case MultiviewLayout::SCENES_ONLY_16_SCENES:
		n = 8;
		break;
	case MultiviewLayout::SCENES_ONLY_9_SCENES:
		n = 6;
		break;
	case MultiviewLayout::SCENES_ONLY_4_SCENES:
		n = 4;
		break;
	default:
		n = 4;
		break;
	}

	w = uint32_t(w * ((1.0f) / n));
	return (cx / 2) - w;
}

void Multiview::Render(uint32_t cx, uint32_t cy)
{
	OBSBasic *main = (OBSBasic *)obs_frontend_get_main_window();

	uint32_t targetCX, targetCY;
	int x, y;
	float scale;

	targetCX = (uint32_t)fw;
	targetCY = (uint32_t)fh;

	GetScaleAndCenterPos(targetCX, targetCY, cx, cy, x, y, scale);

	OBSSource previewSrc = main->GetCurrentSceneSource();
	OBSSource programSrc = main->GetProgramSource();
	bool studioMode = main->IsPreviewProgramMode();

	auto drawBox = [&](float cx, float cy, uint32_t colorVal) {
		gs_effect_t *solid = obs_get_base_effect(OBS_EFFECT_SOLID);
		gs_eparam_t *color = gs_effect_get_param_by_name(solid, "color");

		gs_effect_set_color(color, colorVal);
		while (gs_effect_loop(solid, "Solid"))
			gs_draw_sprite(nullptr, 0, (uint32_t)cx, (uint32_t)cy);
	};

	auto setRegion = [&](float bx, float by, float cx, float cy) {
		float vX = int(x + bx * scale);
		float vY = int(y + by * scale);
		float vCX = int(cx * scale);
		float vCY = int(cy * scale);

		float oL = bx;
		float oT = by;
		float oR = (bx + cx);
		float oB = (by + cy);

		startRegion(vX, vY, vCX, vCY, oL, oR, oT, oB);
	};

	auto calcBaseSource = [&](size_t i) {
		switch (multiviewLayout) {
		case MultiviewLayout::HORIZONTAL_TOP_18_SCENES:
			sourceX = (i % 6) * scenesCX;
			sourceY = pvwprgCY + (i / 6) * scenesCY;
			break;
		case MultiviewLayout::HORIZONTAL_TOP_24_SCENES:
			sourceX = (i % 6) * scenesCX;
			sourceY = pvwprgCY + (i / 6) * scenesCY;
			break;
		case MultiviewLayout::VERTICAL_LEFT_8_SCENES:
			sourceX = pvwprgCX;
			sourceY = (i / 2) * scenesCY;
			if (i % 2 != 0)
				sourceX += scenesCX;
			break;
		case MultiviewLayout::VERTICAL_RIGHT_8_SCENES:
			sourceX = 0;
			sourceY = (i / 2) * scenesCY;
			if (i % 2 != 0)
				sourceX = scenesCX;
			break;
		case MultiviewLayout::HORIZONTAL_BOTTOM_8_SCENES:
			if (i < 4) {
				sourceX = (float(i) * scenesCX);
				sourceY = 0;
			} else {
				sourceX = (float(i - 4) * scenesCX);
				sourceY = scenesCY;
			}
			break;
		case MultiviewLayout::SCENES_ONLY_4_SCENES:
			sourceX = (i % 2) * scenesCX;
			sourceY = (i / 2) * scenesCY;
			break;
		case MultiviewLayout::SCENES_ONLY_9_SCENES:
			sourceX = (i % 3) * scenesCX;
			sourceY = (i / 3) * scenesCY;
			break;
		case MultiviewLayout::SCENES_ONLY_16_SCENES:
			sourceX = (i % 4) * scenesCX;
			sourceY = (i / 4) * scenesCY;
			break;
		case MultiviewLayout::SCENES_ONLY_25_SCENES:
			sourceX = (i % 5) * scenesCX;
			sourceY = (i / 5) * scenesCY;
			break;
		default: // MultiviewLayout::HORIZONTAL_TOP_8_SCENES:
			if (i < 4) {
				sourceX = (float(i) * scenesCX);
				sourceY = pvwprgCY;
			} else {
				sourceX = (float(i - 4) * scenesCX);
				sourceY = pvwprgCY + scenesCY;
			}
		}
		siX = sourceX + thickness;
		siY = sourceY + thickness;
	};

	auto calcPreviewProgram = [&](bool program) {
		switch (multiviewLayout) {
		case MultiviewLayout::HORIZONTAL_TOP_24_SCENES:
			sourceX = thickness + pvwprgCX / 2;
			sourceY = thickness;
			labelX = offset + pvwprgCX / 2;
			labelY = pvwprgCY;
			if (program) {
				sourceX += pvwprgCX;
				labelX += pvwprgCX;
			}
			break;
		case MultiviewLayout::VERTICAL_LEFT_8_SCENES:
			sourceX = thickness;
			sourceY = pvwprgCY + thickness;
			labelX = offset;
			labelY = pvwprgCY * 2;
			if (program) {
				sourceY = thickness;
				labelY = pvwprgCY;
			}
			break;
		case MultiviewLayout::VERTICAL_RIGHT_8_SCENES:
			sourceX = pvwprgCX + thickness;
			sourceY = pvwprgCY + thickness;
			labelX = pvwprgCX + offset;
			labelY = pvwprgCY * 2;
			if (program) {
				sourceY = thickness;
				labelY = pvwprgCY;
			}
			break;
		case MultiviewLayout::HORIZONTAL_BOTTOM_8_SCENES:
			sourceX = thickness;
			sourceY = pvwprgCY + thickness;
			labelX = offset;
			labelY = pvwprgCY * 2;
			if (program) {
				sourceX += pvwprgCX;
				labelX += pvwprgCX;
			}
			break;
		case MultiviewLayout::SCENES_ONLY_4_SCENES:
		case MultiviewLayout::SCENES_ONLY_9_SCENES:
		case MultiviewLayout::SCENES_ONLY_16_SCENES:
			sourceX = thickness;
			sourceY = thickness;
			labelX = offset;
			break;
		default: // MultiviewLayout::HORIZONTAL_TOP_8_SCENES and 18_SCENES
			sourceX = thickness;
			sourceY = thickness;
			labelX = offset;
			labelY = pvwprgCY;
			if (program) {
				sourceX += pvwprgCX;
				labelX += pvwprgCX;
			}
		}
	};

	auto paintAreaWithColor = [&](float tx, float ty, float cx, float cy, uint32_t color) {
		gs_matrix_push();
		gs_matrix_translate3f(tx, ty, 0.0f);
		drawBox(cx, cy, color);
		gs_matrix_pop();
	};

	// Define the whole usable region for the multiview
	startRegion(x, y, targetCX * scale, targetCY * scale, 0.0f, fw, 0.0f, fh);

	// Change the background color to highlight all sources
	drawBox(fw, fh, outerColor);

	/* ----------------------------- */
	/* draw sources                  */

	for (size_t i = 0; i < maxSrcs; i++) {
		// Handle all the offsets
		calcBaseSource(i);

		if (i >= multiviewScenes.size()) {
			// Just paint the background and continue
			paintAreaWithColor(sourceX, sourceY, scenesCX, scenesCY, outerColor);
			paintAreaWithColor(siX, siY, siCX, siCY, backgroundColor);
			continue;
		}

		OBSSource src = OBSGetStrongRef(multiviewScenes[i]);

		// We have a source. Now chose the proper highlight color
		uint32_t colorVal = outerColor;
		if (src == programSrc)
			colorVal = programColor;
		else if (src == previewSrc)
			colorVal = studioMode ? previewColor : programColor;

		// Paint the background
		paintAreaWithColor(sourceX, sourceY, scenesCX, scenesCY, colorVal);
		paintAreaWithColor(siX, siY, siCX, siCY, backgroundColor);

		/* ----------- */

		// Render the source
		gs_matrix_push();
		gs_matrix_translate3f(siX, siY, 0.0f);
		gs_matrix_scale3f(siScaleX, siScaleY, 1.0f);
		setRegion(siX, siY, siCX, siCY);
		obs_source_video_render(src);
		endRegion();
		gs_matrix_pop();

		/* ----------- */

		// Render the label
		if (!drawLabel)
			continue;

		obs_source *label = multiviewLabels[i + 2];
		if (!label)
			continue;

		offset = labelOffset(multiviewLayout, label, scenesCX);

		gs_matrix_push();
		gs_matrix_translate3f(sourceX + offset,
				      sourceY + scenesCY - (obs_source_get_height(label) * ppiScaleY) - (thickness * 3),
				      0.0f);
		gs_matrix_scale3f(ppiScaleX, ppiScaleY, 1.0f);
		drawBox(obs_source_get_width(label), obs_source_get_height(label) + thicknessx2, labelColor);
		gs_matrix_translate3f(0, thickness, 0.0f);
		obs_source_video_render(label);
		gs_matrix_pop();
	}

	if (multiviewLayout == MultiviewLayout::SCENES_ONLY_4_SCENES ||
	    multiviewLayout == MultiviewLayout::SCENES_ONLY_9_SCENES ||
	    multiviewLayout == MultiviewLayout::SCENES_ONLY_16_SCENES ||
	    multiviewLayout == MultiviewLayout::SCENES_ONLY_25_SCENES) {
		endRegion();
		return;
	}

	/* ----------------------------- */
	/* draw preview                  */

	obs_source_t *previewLabel = multiviewLabels[0];
	offset = labelOffset(multiviewLayout, previewLabel, pvwprgCX);
	calcPreviewProgram(false);

	// Paint the background
	paintAreaWithColor(sourceX, sourceY, ppiCX, ppiCY, backgroundColor);

	// Scale and Draw the preview
	gs_matrix_push();
	gs_matrix_translate3f(sourceX, sourceY, 0.0f);
	gs_matrix_scale3f(ppiScaleX, ppiScaleY, 1.0f);
	setRegion(sourceX, sourceY, ppiCX, ppiCY);
	if (studioMode)
		obs_source_video_render(previewSrc);
	else
		obs_render_main_texture();

	if (drawSafeArea) {
		RenderSafeAreas(actionSafeMargin, targetCX, targetCY);
		RenderSafeAreas(graphicsSafeMargin, targetCX, targetCY);
		RenderSafeAreas(fourByThreeSafeMargin, targetCX, targetCY);
		RenderSafeAreas(leftLine, targetCX, targetCY);
		RenderSafeAreas(topLine, targetCX, targetCY);
		RenderSafeAreas(rightLine, targetCX, targetCY);
	}

	endRegion();
	gs_matrix_pop();

	/* ----------- */

	// Draw the Label
	if (drawLabel) {
		gs_matrix_push();
		gs_matrix_translate3f(
			labelX, labelY - (obs_source_get_height(previewLabel) * ppiScaleY) - (thickness * 3), 0.0f);
		gs_matrix_scale3f(ppiScaleX, ppiScaleY, 1.0f);
		drawBox(obs_source_get_width(previewLabel), obs_source_get_height(previewLabel) + thicknessx2,
			labelColor);
		gs_matrix_translate3f(0, thickness, 0.0f);
		obs_source_video_render(previewLabel);
		gs_matrix_pop();
	}

	/* ----------------------------- */
	/* draw program                  */

	obs_source_t *programLabel = multiviewLabels[1];
	offset = labelOffset(multiviewLayout, programLabel, pvwprgCX);
	calcPreviewProgram(true);

	paintAreaWithColor(sourceX, sourceY, ppiCX, ppiCY, backgroundColor);

	// Scale and Draw the program
	gs_matrix_push();
	gs_matrix_translate3f(sourceX, sourceY, 0.0f);
	gs_matrix_scale3f(ppiScaleX, ppiScaleY, 1.0f);
	setRegion(sourceX, sourceY, ppiCX, ppiCY);
	obs_render_main_texture();
	endRegion();
	gs_matrix_pop();

	/* ----------- */

	// Draw the Label
	if (drawLabel) {
		gs_matrix_push();
		gs_matrix_translate3f(
			labelX, labelY - (obs_source_get_height(programLabel) * ppiScaleY) - (thickness * 3), 0.0f);
		gs_matrix_scale3f(ppiScaleX, ppiScaleY, 1.0f);
		drawBox(obs_source_get_width(programLabel), obs_source_get_height(programLabel) + thicknessx2,
			labelColor);
		gs_matrix_translate3f(0, thickness, 0.0f);
		obs_source_video_render(programLabel);
		gs_matrix_pop();
	}

	// Region for future usage with additional info.
	if (multiviewLayout == MultiviewLayout::HORIZONTAL_TOP_24_SCENES) {
		// Just paint the background for now
		paintAreaWithColor(thickness, thickness, siCX, siCY * 2 + thicknessx2, backgroundColor);
		paintAreaWithColor(thickness + 2.5 * (thicknessx2 + ppiCX), thickness, siCX, siCY * 2 + thicknessx2,
				   backgroundColor);
	}

	endRegion();
}

OBSSource Multiview::GetSourceByPosition(int x, int y)
{
	int pos = -1;
	QWidget *rec = QApplication::activeWindow();
	if (!rec)
		return nullptr;
	int cx = rec->width();
	int cy = rec->height();
	int minX = 0;
	int minY = 0;
	int maxX = cx;
	int maxY = cy;

	switch (multiviewLayout) {
	case MultiviewLayout::HORIZONTAL_TOP_18_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
		}
		minY = cy / 2;

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 6);
		pos += ((y - minY) / ((maxY - minY) / 3)) * 6;

		break;
	case MultiviewLayout::HORIZONTAL_TOP_24_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
			minY = cy / 3;
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
			minY = (cy / 2) - (validY / 6);
		}

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 6);
		pos += ((y - minY) / ((maxY - minY) / 4)) * 6;

		break;
	case MultiviewLayout::VERTICAL_LEFT_8_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			minY = (cy / 2) - (validY / 2);
			maxY = (cy / 2) + (validY / 2);
		}

		minX = cx / 2;

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = 2 * ((y - minY) / ((maxY - minY) / 4));
		if (x > minX + ((maxX - minX) / 2))
			pos++;
		break;
	case MultiviewLayout::VERTICAL_RIGHT_8_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
		} else {
			int validY = cx / ratio;
			minY = (cy / 2) - (validY / 2);
			maxY = (cy / 2) + (validY / 2);
		}

		maxX = (cx / 2);

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = 2 * ((y - minY) / ((maxY - minY) / 4));
		if (x > minX + ((maxX - minX) / 2))
			pos++;
		break;
	case MultiviewLayout::HORIZONTAL_BOTTOM_8_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			minY = (cy / 2) - (validY / 2);
		}

		maxY = (cy / 2);

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 4);
		if (y > minY + ((maxY - minY) / 2))
			pos += 4;
		break;
	case MultiviewLayout::SCENES_ONLY_4_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
			minY = (cy / 2) - (validY / 2);
		}

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 2);
		pos += ((y - minY) / ((maxY - minY) / 2)) * 2;

		break;
	case MultiviewLayout::SCENES_ONLY_9_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
			minY = (cy / 2) - (validY / 2);
		}

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 3);
		pos += ((y - minY) / ((maxY - minY) / 3)) * 3;

		break;
	case MultiviewLayout::SCENES_ONLY_16_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
			minY = (cy / 2) - (validY / 2);
		}

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 4);
		pos += ((y - minY) / ((maxY - minY) / 4)) * 4;

		break;
	case MultiviewLayout::SCENES_ONLY_25_SCENES:
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
			minY = (cy / 2) - (validY / 2);
		}

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 5);
		pos += ((y - minY) / ((maxY - minY) / 5)) * 5;

		break;
	default: // MultiviewLayout::HORIZONTAL_TOP_8_SCENES
		if (float(cx) / float(cy) > ratio) {
			int validX = cy * ratio;
			minX = (cx / 2) - (validX / 2);
			maxX = (cx / 2) + (validX / 2);
		} else {
			int validY = cx / ratio;
			maxY = (cy / 2) + (validY / 2);
		}

		minY = (cy / 2);

		if (x < minX || x > maxX || y < minY || y > maxY)
			break;

		pos = (x - minX) / ((maxX - minX) / 4);
		if (y > minY + ((maxY - minY) / 2))
			pos += 4;
	}

	if (pos < 0 || pos >= (int)multiviewScenes.size())
		return nullptr;

	return OBSGetStrongRef(multiviewScenes[pos]);
}