OXYGENHUB
◆ main openmsx / src / imgui / ImGuiAdjust.cc
3.3 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "ImGuiAdjust.hh"
2
3 
#include <imgui.h>
4
5 
#include <optional>
6
7 
namespace openmsx {
8
9 
// Adjust one dimension. So call it once for X, once for Y.
10 
[[nodiscard]] static std::optional<float> adjustWindowPositionForResizedViewPort(
11 
	float oldViewPortSize, float newViewPortSize, float relWindowPos, float windowSize)
12 
{
13 
	// Window can no longer fit in new viewPort.
14 
	if (newViewPortSize < windowSize) return {};
15
16 
	// Closer to left or right border (or top/bottom)?
17 
	float windowEndPos = relWindowPos + windowSize;
18 
	float distanceToLeft = relWindowPos;
19 
	float distanceToRight = oldViewPortSize - windowEndPos;
20
21 
	if (distanceToLeft < distanceToRight) {
22 
		// Maintain the distance to the closest border.
23 
		float newDistanceToLeft = distanceToLeft;
24 
		float newWindowPos = newDistanceToLeft;
25 
		float newWindowEndPos = newWindowPos + windowSize;
26 
		float newDistanceToRight = newViewPortSize - newWindowEndPos;
27
28 
		// Check if the other border becomes the closer one.
29 
		if (newDistanceToLeft > newDistanceToRight) {
30 
			// If so, place in the middle instead.
31 
			newWindowPos = (newViewPortSize - windowSize) * 0.5f;
32 
		}
33 
		return newWindowPos;
34 
	} else {
35 
		float newDistanceToRight = distanceToRight;
36 
		float newWidowEndPos = newViewPortSize - newDistanceToRight;
37 
		float newWindowPos = newWidowEndPos - windowSize;
38 
		float newDistanceToLeft = newWindowPos;
39 
		if (newDistanceToRight > newDistanceToLeft) {
40 
			newWindowPos = (newViewPortSize - windowSize) * 0.5f;
41 
		}
42 
		return newWindowPos;
43 
	}
44 
}
45
46 
void AdjustWindowInMainViewPort::pre()
47 
{
48 
	if (setMainViewPort) {
49 
		setMainViewPort = false;
50 
		const auto* mainViewPort = ImGui::GetMainViewport();
51 
		ImGui::SetNextWindowViewport(mainViewPort->ID);
52 
	}
53 
}
54
55 
bool AdjustWindowInMainViewPort::post()
56 
{
57 
	const auto* mainViewPort = ImGui::GetMainViewport();
58 
	const auto* windowViewPort = ImGui::GetWindowViewport();
59 
	bool isOnMainViewPort = windowViewPort == mainViewPort;
60 
	gl::vec2 newViewPortSize = mainViewPort->Size;
61 
	gl::vec2 mainViewPortPos = mainViewPort->Pos;
62 
	gl::vec2 relWindowPos = gl::vec2(ImGui::GetWindowPos()) - mainViewPortPos;
63
64 
	if (oldIsOnMainViewPort && (oldViewPortSize != newViewPortSize)) {
65 
		gl::vec2 windowSize = ImGui::GetWindowSize();
66 
		if (!isOnMainViewPort) {
67 
			// previous frame we were in the main view port,
68 
			// but now, after main view port has resized,
69 
			// we're not. Try to pull us back into the main
70 
			// view port.
71 
			setMainViewPort = true;
72 
			isOnMainViewPort = true;
73 
			relWindowPos = oldRelWindowPos;
74 
		}
75 
		auto newPosX = adjustWindowPositionForResizedViewPort(
76 
			oldViewPortSize.x, newViewPortSize.x, relWindowPos.x, windowSize.x);
77 
		auto newPosY = adjustWindowPositionForResizedViewPort(
78 
			oldViewPortSize.y, newViewPortSize.y, relWindowPos.y, windowSize.y);
79 
		if (newPosX && newPosY) {
80 
			relWindowPos = gl::vec2{*newPosX, *newPosY};
81 
			ImGui::SetWindowPos(mainViewPortPos + relWindowPos);
82 
		}
83 
	}
84
85 
	// data for next frame
86 
	oldViewPortSize = newViewPortSize;
87 
	oldRelWindowPos = relWindowPos;
88 
	oldIsOnMainViewPort = isOnMainViewPort;
89
90 
	return isOnMainViewPort;
91 
}
92
93 
void AdjustWindowInMainViewPort::save(ImGuiTextBuffer& buf)
94 
{
95 
	savePersistent(buf, *this, persistentElements);
96 
}
97
98 
bool AdjustWindowInMainViewPort::loadLine(std::string_view name, zstring_view value)
99 
{
100 
	return loadOnePersistent(name, value, *this, persistentElements);
101 
}
102
103 
} // namespace openmsx