Arrange windows on desktop

sway/tree/layout.c

@@ -1,10 +1,14 @@
 #define _POSIX_C_SOURCE 200809L
 #include <ctype.h>
+#include <math.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
+#include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_layout.h>
 #include "sway/container.h"
+#include "sway/output.h"
+#include "sway/view.h"
 #include "list.h"
 #include "log.h"
 
@@ -70,3 +74,204 @@ static int sort_workspace_cmp_qsort(const void *_a, const void *_b) {
 void sort_workspaces(swayc_t *output) {
 	list_stable_sort(output->children, sort_workspace_cmp_qsort);
 }
+
+static void apply_horiz_layout(swayc_t *container, const double x,
+				const double y, const double width,
+				const double height, const int start,
+				const int end);
+
+static void apply_vert_layout(swayc_t *container, const double x,
+				const double y, const double width,
+				const double height, const int start,
+				const int end);
+
+void arrange_windows(swayc_t *container, double width, double height) {
+	int i;
+	if (width == -1 || height == -1) {
+		width = container->width;
+		height = container->height;
+	}
+	// pixels are indivisible. if we don't round the pixels, then the view
+	// calculations will be off (e.g. 50.5 + 50.5 = 101, but in reality it's
+	// 50 + 50 = 100). doing it here cascades properly to all width/height/x/y.
+	width = floor(width);
+	height = floor(height);
+
+	sway_log(L_DEBUG, "Arranging layout for %p %s %fx%f+%f,%f", container,
+		 container->name, container->width, container->height, container->x,
+		 container->y);
+
+	double x = 0, y = 0;
+	switch (container->type) {
+	case C_ROOT:
+		// TODO: wlr_output_layout probably
+		for (i = 0; i < container->children->length; ++i) {
+			swayc_t *output = container->children->items[i];
+			sway_log(L_DEBUG, "Arranging output '%s' at %f,%f",
+					output->name, output->x, output->y);
+			arrange_windows(output, -1, -1);
+		}
+		return;
+	case C_OUTPUT:
+		{
+			int _width, _height;
+			wlr_output_effective_resolution(
+					container->sway_output->wlr_output, &_width, &_height);
+			width = container->width = _width;
+			height = container->height = _height;
+		}
+		// arrange all workspaces:
+		for (i = 0; i < container->children->length; ++i) {
+			swayc_t *child = container->children->items[i];
+			arrange_windows(child, -1, -1);
+		}
+		return;
+	case C_WORKSPACE:
+		{
+			swayc_t *output = swayc_parent_by_type(container, C_OUTPUT);
+			width = output->width, height = output->height;
+			container->x = x;
+			container->y = y;
+			width = container->width;
+			height = container->height;
+			sway_log(L_DEBUG, "Arranging workspace '%s' at %f, %f",
+					container->name, container->x, container->y);
+		}
+		// children are properly handled below
+		break;
+	case C_VIEW:
+		{
+			container->width = width;
+			container->height = height;
+			container->sway_view->iface.set_dimensions(container->sway_view,
+					container->width, container->height);
+			sway_log(L_DEBUG, "Set view to %.f x %.f @ %.f, %.f",
+					container->width, container->height,
+					container->x, container->y);
+		}
+		return;
+	default:
+		container->width = width;
+		container->height = height;
+		x = container->x;
+		y = container->y;
+		break;
+	}
+
+	switch (container->layout) {
+	case L_HORIZ:
+		apply_horiz_layout(container, x, y, width, height, 0,
+			container->children->length);
+		break;
+	case L_VERT:
+		apply_vert_layout(container, x, y, width, height, 0,
+			container->children->length);
+		break;
+	default:
+		sway_log(L_DEBUG, "TODO: arrange layout type %d", container->layout);
+		apply_horiz_layout(container, x, y, width, height, 0,
+			container->children->length);
+		break;
+	}
+}
+
+static void apply_horiz_layout(swayc_t *container,
+		const double x, const double y,
+		const double width, const double height,
+		const int start, const int end) {
+	double scale = 0;
+	// Calculate total width
+	for (int i = start; i < end; ++i) {
+		double *old_width = &((swayc_t *)container->children->items[i])->width;
+		if (*old_width <= 0) {
+			if (end - start > 1) {
+				*old_width = width / (end - start - 1);
+			} else {
+				*old_width = width;
+			}
+		}
+		scale += *old_width;
+	}
+	scale = width / scale;
+
+	// Resize windows
+	double child_x = x;
+	if (scale > 0.1) {
+		sway_log(L_DEBUG, "Arranging %p horizontally", container);
+		for (int i = start; i < end; ++i) {
+			swayc_t *child = container->children->items[i];
+			sway_log(L_DEBUG,
+				 "Calculating arrangement for %p:%d (will scale %f by %f)",
+				 child, child->type, width, scale);
+			child->x = child_x;
+			child->y = y;
+
+			if (i == end - 1) {
+				double remaining_width = x + width - child_x;
+				arrange_windows(child, remaining_width, height);
+			} else {
+				arrange_windows(child, child->width * scale, height);
+			}
+			child_x += child->width;
+		}
+
+		// update focused view border last because it may
+		// depend on the title bar geometry of its siblings.
+		/* TODO WLR
+		if (focused && container->children->length > 1) {
+			update_container_border(focused);
+		}
+		*/
+	}
+}
+
+void apply_vert_layout(swayc_t *container,
+		const double x, const double y,
+		const double width, const double height, const int start,
+		const int end) {
+	int i;
+	double scale = 0;
+	// Calculate total height
+	for (i = start; i < end; ++i) {
+		double *old_height = &((swayc_t *)container->children->items[i])->height;
+		if (*old_height <= 0) {
+			if (end - start > 1) {
+				*old_height = height / (end - start - 1);
+			} else {
+				*old_height = height;
+			}
+		}
+		scale += *old_height;
+	}
+	scale = height / scale;
+
+	// Resize
+	double child_y = y;
+	if (scale > 0.1) {
+		sway_log(L_DEBUG, "Arranging %p vertically", container);
+		for (i = start; i < end; ++i) {
+			swayc_t *child = container->children->items[i];
+			sway_log(L_DEBUG,
+				 "Calculating arrangement for %p:%d (will scale %f by %f)",
+				 child, child->type, height, scale);
+			child->x = x;
+			child->y = child_y;
+
+			if (i == end - 1) {
+				double remaining_height = y + height - child_y;
+				arrange_windows(child, width, remaining_height);
+			} else {
+				arrange_windows(child, width, child->height * scale);
+			}
+			child_y += child->height;
+		}
+
+		// update focused view border last because it may
+		// depend on the title bar geometry of its siblings.
+		/* TODO WLR
+		if (focused && container->children->length > 1) {
+			update_container_border(focused);
+		}
+		*/
+	}
+}