zgui/libs/node_editor/imgui_canvas.cpp

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# ifndef IMGUI_DEFINE_MATH_OPERATORS
# define IMGUI_DEFINE_MATH_OPERATORS
# endif
# include "imgui_canvas.h"
# include <type_traits>
// https://stackoverflow.com/a/36079786
# define DECLARE_HAS_MEMBER(__trait_name__, __member_name__) \
\
template <typename __boost_has_member_T__> \
class __trait_name__ \
{ \
using check_type = ::std::remove_const_t<__boost_has_member_T__>; \
struct no_type {char x[2];}; \
using yes_type = char; \
\
struct base { void __member_name__() {}}; \
struct mixin : public base, public check_type {}; \
\
template <void (base::*)()> struct aux {}; \
\
template <typename U> static no_type test(aux<&U::__member_name__>*); \
template <typename U> static yes_type test(...); \
\
public: \
\
static constexpr bool value = (sizeof(yes_type) == sizeof(test<mixin>(0))); \
}
// Special sentinel value. This needs to be unique, so allow it to be overridden in the user's ImGui config
# ifndef ImDrawCallback_ImCanvas
# define ImDrawCallback_ImCanvas (ImDrawCallback)(-2)
# endif
namespace ImCanvasDetails {
DECLARE_HAS_MEMBER(HasFringeScale, _FringeScale);
struct FringeScaleRef
{
// Overload is present when ImDrawList does have _FringeScale member variable.
template <typename T>
static float& Get(typename std::enable_if<HasFringeScale<T>::value, T>::type* drawList)
{
return drawList->_FringeScale;
}
// Overload is present when ImDrawList does not have _FringeScale member variable.
template <typename T>
static float& Get(typename std::enable_if<!HasFringeScale<T>::value, T>::type*)
{
static float placeholder = 1.0f;
return placeholder;
}
};
DECLARE_HAS_MEMBER(HasVtxCurrentOffset, _VtxCurrentOffset);
struct VtxCurrentOffsetRef
{
// Overload is present when ImDrawList does have _FringeScale member variable.
template <typename T>
static unsigned int& Get(typename std::enable_if<HasVtxCurrentOffset<T>::value, T>::type* drawList)
{
return drawList->_VtxCurrentOffset;
}
// Overload is present when ImDrawList does not have _FringeScale member variable.
template <typename T>
static unsigned int& Get(typename std::enable_if<!HasVtxCurrentOffset<T>::value, T>::type* drawList)
{
return drawList->_CmdHeader.VtxOffset;
}
};
} // namespace ImCanvasDetails
// Returns a reference to _FringeScale extension to ImDrawList
//
// If ImDrawList does not have _FringeScale a placeholder is returned.
static inline float& ImFringeScaleRef(ImDrawList* drawList)
{
using namespace ImCanvasDetails;
return FringeScaleRef::Get<ImDrawList>(drawList);
}
static inline unsigned int& ImVtxOffsetRef(ImDrawList* drawList)
{
using namespace ImCanvasDetails;
return VtxCurrentOffsetRef::Get<ImDrawList>(drawList);
}
static inline ImVec2 ImSelectPositive(const ImVec2& lhs, const ImVec2& rhs) { return ImVec2(lhs.x > 0.0f ? lhs.x : rhs.x, lhs.y > 0.0f ? lhs.y : rhs.y); }
bool ImGuiEx::Canvas::Begin(const char* id, const ImVec2& size)
{
return Begin(ImGui::GetID(id), size);
}
bool ImGuiEx::Canvas::Begin(ImGuiID id, const ImVec2& size)
{
IM_ASSERT(m_InBeginEnd == false);
m_WidgetPosition = ImGui::GetCursorScreenPos();
m_WidgetSize = ImSelectPositive(size, ImGui::GetContentRegionAvail());
m_WidgetRect = ImRect(m_WidgetPosition, m_WidgetPosition + m_WidgetSize);
m_DrawList = ImGui::GetWindowDrawList();
UpdateViewTransformPosition();
# if IMGUI_VERSION_NUM > 18415
if (ImGui::IsClippedEx(m_WidgetRect, id))
return false;
# else
if (ImGui::IsClippedEx(m_WidgetRect, id, false))
return false;
# endif
// Save current channel, so we can assert when user
// call canvas API with different one.
m_ExpectedChannel = m_DrawList->_Splitter._Current;
// #debug: Canvas content.
//m_DrawList->AddRectFilled(m_StartPos, m_StartPos + m_CurrentSize, IM_COL32(0, 0, 0, 64));
//m_DrawList->AddRect(m_WidgetRect.Min, m_WidgetRect.Max, IM_COL32(255, 0, 255, 64));
ImGui::SetCursorScreenPos(ImVec2(0.0f, 0.0f));
# if IMGUI_EX_CANVAS_DEFERED()
m_Ranges.resize(0);
# endif
SaveInputState();
SaveViewportState();
// Record cursor max to prevent scrollbars from appearing.
m_WindowCursorMaxBackup = ImGui::GetCurrentWindow()->DC.CursorMaxPos;
EnterLocalSpace();
# if IMGUI_VERSION_NUM >= 18967
ImGui::SetNextItemAllowOverlap();
# endif
// Emit dummy widget matching bounds of the canvas.
ImGui::SetCursorScreenPos(m_ViewRect.Min);
ImGui::Dummy(m_ViewRect.GetSize());
ImGui::SetCursorScreenPos(ImVec2(0.0f, 0.0f));
m_InBeginEnd = true;
return true;
}
void ImGuiEx::Canvas::End()
{
// If you're here your call to Begin() returned false,
// or Begin() wasn't called at all.
IM_ASSERT(m_InBeginEnd == true);
// If you're here, please make sure you do not interleave
// channel splitter with canvas.
// Always call canvas function with using same channel.
IM_ASSERT(m_DrawList->_Splitter._Current == m_ExpectedChannel);
//auto& io = ImGui::GetIO();
// Check: Unmatched calls to Suspend() / Resume(). Please check your code.
IM_ASSERT(m_SuspendCounter == 0);
LeaveLocalSpace();
ImGui::GetCurrentWindow()->DC.CursorMaxPos = m_WindowCursorMaxBackup;
# if IMGUI_VERSION_NUM < 18967
ImGui::SetItemAllowOverlap();
# endif
// Emit dummy widget matching bounds of the canvas.
ImGui::SetCursorScreenPos(m_WidgetPosition);
ImGui::Dummy(m_WidgetSize);
// #debug: Rect around canvas. Content should be inside these bounds.
//m_DrawList->AddRect(m_WidgetPosition - ImVec2(1.0f, 1.0f), m_WidgetPosition + m_WidgetSize + ImVec2(1.0f, 1.0f), IM_COL32(196, 0, 0, 255));
m_InBeginEnd = false;
}
void ImGuiEx::Canvas::SetView(const ImVec2& origin, float scale)
{
SetView(CanvasView(origin, scale));
}
void ImGuiEx::Canvas::SetView(const CanvasView& view)
{
if (m_InBeginEnd)
LeaveLocalSpace();
if (m_View.Origin.x != view.Origin.x || m_View.Origin.y != view.Origin.y)
{
m_View.Origin = view.Origin;
UpdateViewTransformPosition();
}
if (m_View.Scale != view.Scale)
{
m_View.Scale = view.Scale;
m_View.InvScale = view.InvScale;
}
if (m_InBeginEnd)
EnterLocalSpace();
}
void ImGuiEx::Canvas::CenterView(const ImVec2& canvasPoint)
{
auto view = CalcCenterView(canvasPoint);
SetView(view);
}
ImGuiEx::CanvasView ImGuiEx::Canvas::CalcCenterView(const ImVec2& canvasPoint) const
{
auto localCenter = ToLocal(m_WidgetPosition + m_WidgetSize * 0.5f);
auto localOffset = canvasPoint - localCenter;
auto offset = FromLocalV(localOffset);
return CanvasView{ m_View.Origin - offset, m_View.Scale };
}
void ImGuiEx::Canvas::CenterView(const ImRect& canvasRect)
{
auto view = CalcCenterView(canvasRect);
SetView(view);
}
ImGuiEx::CanvasView ImGuiEx::Canvas::CalcCenterView(const ImRect& canvasRect) const
{
auto canvasRectSize = canvasRect.GetSize();
if (canvasRectSize.x <= 0.0f || canvasRectSize.y <= 0.0f)
return View();
auto widgetAspectRatio = m_WidgetSize.y > 0.0f ? m_WidgetSize.x / m_WidgetSize.y : 0.0f;
auto canvasRectAspectRatio = canvasRectSize.y > 0.0f ? canvasRectSize.x / canvasRectSize.y : 0.0f;
if (widgetAspectRatio <= 0.0f || canvasRectAspectRatio <= 0.0f)
return View();
auto newOrigin = m_View.Origin;
auto newScale = m_View.Scale;
if (canvasRectAspectRatio > widgetAspectRatio)
{
// width span across view
newScale = m_WidgetSize.x / canvasRectSize.x;
newOrigin = canvasRect.Min * -newScale;
newOrigin.y += (m_WidgetSize.y - canvasRectSize.y * newScale) * 0.5f;
}
else
{
// height span across view
newScale = m_WidgetSize.y / canvasRectSize.y;
newOrigin = canvasRect.Min * -newScale;
newOrigin.x += (m_WidgetSize.x - canvasRectSize.x * newScale) * 0.5f;
}
return CanvasView{ newOrigin, newScale };
}
void ImGuiEx::Canvas::Suspend()
{
// If you're here, please make sure you do not interleave
// channel splitter with canvas.
// Always call canvas function with using same channel.
IM_ASSERT(m_DrawList->_Splitter._Current == m_ExpectedChannel);
if (m_SuspendCounter == 0)
LeaveLocalSpace();
++m_SuspendCounter;
}
void ImGuiEx::Canvas::Resume()
{
// If you're here, please make sure you do not interleave
// channel splitter with canvas.
// Always call canvas function with using same channel.
IM_ASSERT(m_DrawList->_Splitter._Current == m_ExpectedChannel);
// Check: Number of calls to Resume() do not match calls to Suspend(). Please check your code.
IM_ASSERT(m_SuspendCounter > 0);
if (--m_SuspendCounter == 0)
EnterLocalSpace();
}
ImVec2 ImGuiEx::Canvas::FromLocal(const ImVec2& point) const
{
return point * m_View.Scale + m_ViewTransformPosition;
}
ImVec2 ImGuiEx::Canvas::FromLocal(const ImVec2& point, const CanvasView& view) const
{
return point * view.Scale + view.Origin + m_WidgetPosition;
}
ImVec2 ImGuiEx::Canvas::FromLocalV(const ImVec2& vector) const
{
return vector * m_View.Scale;
}
ImVec2 ImGuiEx::Canvas::FromLocalV(const ImVec2& vector, const CanvasView& view) const
{
return vector * view.Scale;
}
ImVec2 ImGuiEx::Canvas::ToLocal(const ImVec2& point) const
{
return (point - m_ViewTransformPosition) * m_View.InvScale;
}
ImVec2 ImGuiEx::Canvas::ToLocal(const ImVec2& point, const CanvasView& view) const
{
return (point - view.Origin - m_WidgetPosition) * view.InvScale;
}
ImVec2 ImGuiEx::Canvas::ToLocalV(const ImVec2& vector) const
{
return vector * m_View.InvScale;
}
ImVec2 ImGuiEx::Canvas::ToLocalV(const ImVec2& vector, const CanvasView& view) const
{
return vector * view.InvScale;
}
ImRect ImGuiEx::Canvas::CalcViewRect(const CanvasView& view) const
{
ImRect result;
result.Min = ImVec2(-view.Origin.x, -view.Origin.y) * view.InvScale;
result.Max = (m_WidgetSize - view.Origin) * view.InvScale;
return result;
}
void ImGuiEx::Canvas::UpdateViewTransformPosition()
{
m_ViewTransformPosition = m_View.Origin + m_WidgetPosition;
}
void ImGuiEx::Canvas::SaveInputState()
{
auto& io = ImGui::GetIO();
m_MousePosBackup = io.MousePos;
m_MousePosPrevBackup = io.MousePosPrev;
for (auto i = 0; i < IM_ARRAYSIZE(m_MouseClickedPosBackup); ++i)
m_MouseClickedPosBackup[i] = io.MouseClickedPos[i];
}
void ImGuiEx::Canvas::RestoreInputState()
{
auto& io = ImGui::GetIO();
io.MousePos = m_MousePosBackup;
io.MousePosPrev = m_MousePosPrevBackup;
for (auto i = 0; i < IM_ARRAYSIZE(m_MouseClickedPosBackup); ++i)
io.MouseClickedPos[i] = m_MouseClickedPosBackup[i];
}
void ImGuiEx::Canvas::SaveViewportState()
{
# if defined(IMGUI_HAS_VIEWPORT)
auto window = ImGui::GetCurrentWindow();
auto viewport = ImGui::GetWindowViewport();
m_WindowPosBackup = window->Pos;
m_ViewportPosBackup = viewport->Pos;
m_ViewportSizeBackup = viewport->Size;
# if IMGUI_VERSION_NUM > 18002
m_ViewportWorkPosBackup = viewport->WorkPos;
m_ViewportWorkSizeBackup = viewport->WorkSize;
# else
m_ViewportWorkOffsetMinBackup = viewport->WorkOffsetMin;
m_ViewportWorkOffsetMaxBackup = viewport->WorkOffsetMax;
# endif
# endif
}
void ImGuiEx::Canvas::RestoreViewportState()
{
# if defined(IMGUI_HAS_VIEWPORT)
auto window = ImGui::GetCurrentWindow();
auto viewport = ImGui::GetWindowViewport();
window->Pos = m_WindowPosBackup;
viewport->Pos = m_ViewportPosBackup;
viewport->Size = m_ViewportSizeBackup;
# if IMGUI_VERSION_NUM > 18002
viewport->WorkPos = m_ViewportWorkPosBackup;
viewport->WorkSize = m_ViewportWorkSizeBackup;
# else
viewport->WorkOffsetMin = m_ViewportWorkOffsetMinBackup;
viewport->WorkOffsetMax = m_ViewportWorkOffsetMaxBackup;
# endif
# endif
}
void ImGuiEx::Canvas::EnterLocalSpace()
{
// Prepare ImDrawList for drawing in local coordinate system:
// - determine visible part of the canvas
// - start unique draw command
// - add clip rect matching canvas size
// - record current command index
// - record current vertex write index
// Determine visible part of the canvas. Make it before
// adding new command, to avoid round rip where command
// is removed in PopClipRect() and added again next PushClipRect().
ImGui::PushClipRect(m_WidgetPosition, m_WidgetPosition + m_WidgetSize, true);
auto clipped_clip_rect = m_DrawList->_ClipRectStack.back();
ImGui::PopClipRect();
# if IMGUI_EX_CANVAS_DEFERED()
m_Ranges.resize(m_Ranges.Size + 1);
m_CurrentRange = &m_Ranges.back();
m_CurrentRange->BeginComandIndex = ImMax(m_DrawList->CmdBuffer.Size, 0);
m_CurrentRange->BeginVertexIndex = m_DrawList->_VtxCurrentIdx + ImVtxOffsetRef(m_DrawList);
# endif
m_DrawListCommadBufferSize = ImMax(m_DrawList->CmdBuffer.Size, 0);
m_DrawListStartVertexIndex = m_DrawList->_VtxCurrentIdx + ImVtxOffsetRef(m_DrawList);
// Make sure we do not share draw command with anyone. We don't want to mess
// with someones clip rectangle.
// #FIXME:
// This condition is not enough to avoid when user choose
// to use channel splitter.
//
// To deal with Suspend()/Resume() calls empty draw command
// is always added then splitter is active. Otherwise
// channel merger will collapse our draw command one with
// different clip rectangle.
//
// More investigation is needed. To get to the bottom of this.
if ((!m_DrawList->CmdBuffer.empty() && m_DrawList->CmdBuffer.back().ElemCount > 0) || m_DrawList->_Splitter._Count > 1)
m_DrawList->AddCallback(ImDrawCallback_ImCanvas, nullptr);
m_DrawListFirstCommandIndex = ImMax(m_DrawList->CmdBuffer.Size - 1, 0);
# if defined(IMGUI_HAS_VIEWPORT)
auto window = ImGui::GetCurrentWindow();
window->Pos = ImVec2(0.0f, 0.0f);
auto viewport_min = m_ViewportPosBackup;
auto viewport_max = m_ViewportPosBackup + m_ViewportSizeBackup;
viewport_min.x = (viewport_min.x - m_ViewTransformPosition.x) * m_View.InvScale;
viewport_min.y = (viewport_min.y - m_ViewTransformPosition.y) * m_View.InvScale;
viewport_max.x = (viewport_max.x - m_ViewTransformPosition.x) * m_View.InvScale;
viewport_max.y = (viewport_max.y - m_ViewTransformPosition.y) * m_View.InvScale;
auto viewport = ImGui::GetWindowViewport();
viewport->Pos = viewport_min;
viewport->Size = viewport_max - viewport_min;
# if IMGUI_VERSION_NUM > 18002
viewport->WorkPos = m_ViewportWorkPosBackup * m_View.InvScale;
viewport->WorkSize = m_ViewportWorkSizeBackup * m_View.InvScale;
# else
viewport->WorkOffsetMin = m_ViewportWorkOffsetMinBackup * m_View.InvScale;
viewport->WorkOffsetMax = m_ViewportWorkOffsetMaxBackup * m_View.InvScale;
# endif
# endif
// Clip rectangle in parent canvas space and move it to local space.
clipped_clip_rect.x = (clipped_clip_rect.x - m_ViewTransformPosition.x) * m_View.InvScale;
clipped_clip_rect.y = (clipped_clip_rect.y - m_ViewTransformPosition.y) * m_View.InvScale;
clipped_clip_rect.z = (clipped_clip_rect.z - m_ViewTransformPosition.x) * m_View.InvScale;
clipped_clip_rect.w = (clipped_clip_rect.w - m_ViewTransformPosition.y) * m_View.InvScale;
ImGui::PushClipRect(ImVec2(clipped_clip_rect.x, clipped_clip_rect.y), ImVec2(clipped_clip_rect.z, clipped_clip_rect.w), false);
// Transform mouse position to local space.
auto& io = ImGui::GetIO();
io.MousePos = (m_MousePosBackup - m_ViewTransformPosition) * m_View.InvScale;
io.MousePosPrev = (m_MousePosPrevBackup - m_ViewTransformPosition) * m_View.InvScale;
for (auto i = 0; i < IM_ARRAYSIZE(m_MouseClickedPosBackup); ++i)
io.MouseClickedPos[i] = (m_MouseClickedPosBackup[i] - m_ViewTransformPosition) * m_View.InvScale;
m_ViewRect = CalcViewRect(m_View);;
auto& fringeScale = ImFringeScaleRef(m_DrawList);
m_LastFringeScale = fringeScale;
fringeScale *= m_View.InvScale;
}
void ImGuiEx::Canvas::LeaveLocalSpace()
{
IM_ASSERT(m_DrawList->_Splitter._Current == m_ExpectedChannel);
# if IMGUI_EX_CANVAS_DEFERED()
IM_ASSERT(m_CurrentRange != nullptr);
m_CurrentRange->EndVertexIndex = m_DrawList->_VtxCurrentIdx + ImVtxOffsetRef(m_DrawList);
m_CurrentRange->EndCommandIndex = m_DrawList->CmdBuffer.size();
if (m_CurrentRange->BeginVertexIndex == m_CurrentRange->EndVertexIndex)
{
// Drop empty range
m_Ranges.resize(m_Ranges.Size - 1);
}
m_CurrentRange = nullptr;
# endif
// Move vertices to screen space.
auto vertex = m_DrawList->VtxBuffer.Data + m_DrawListStartVertexIndex;
auto vertexEnd = m_DrawList->VtxBuffer.Data + m_DrawList->_VtxCurrentIdx + ImVtxOffsetRef(m_DrawList);
// If canvas view is not scaled take a faster path.
if (m_View.Scale != 1.0f)
{
while (vertex < vertexEnd)
{
vertex->pos.x = vertex->pos.x * m_View.Scale + m_ViewTransformPosition.x;
vertex->pos.y = vertex->pos.y * m_View.Scale + m_ViewTransformPosition.y;
++vertex;
}
// Move clip rectangles to screen space.
for (int i = m_DrawListFirstCommandIndex; i < m_DrawList->CmdBuffer.size(); ++i)
{
auto& command = m_DrawList->CmdBuffer[i];
command.ClipRect.x = command.ClipRect.x * m_View.Scale + m_ViewTransformPosition.x;
command.ClipRect.y = command.ClipRect.y * m_View.Scale + m_ViewTransformPosition.y;
command.ClipRect.z = command.ClipRect.z * m_View.Scale + m_ViewTransformPosition.x;
command.ClipRect.w = command.ClipRect.w * m_View.Scale + m_ViewTransformPosition.y;
}
}
else
{
while (vertex < vertexEnd)
{
vertex->pos.x = vertex->pos.x + m_ViewTransformPosition.x;
vertex->pos.y = vertex->pos.y + m_ViewTransformPosition.y;
++vertex;
}
// Move clip rectangles to screen space.
for (int i = m_DrawListFirstCommandIndex; i < m_DrawList->CmdBuffer.size(); ++i)
{
auto& command = m_DrawList->CmdBuffer[i];
command.ClipRect.x = command.ClipRect.x + m_ViewTransformPosition.x;
command.ClipRect.y = command.ClipRect.y + m_ViewTransformPosition.y;
command.ClipRect.z = command.ClipRect.z + m_ViewTransformPosition.x;
command.ClipRect.w = command.ClipRect.w + m_ViewTransformPosition.y;
}
}
// Remove sentinel draw command if present
if (m_DrawListCommadBufferSize > 0)
{
if (m_DrawList->CmdBuffer.size() > m_DrawListCommadBufferSize && m_DrawList->CmdBuffer[m_DrawListCommadBufferSize].UserCallback == ImDrawCallback_ImCanvas)
m_DrawList->CmdBuffer.erase(m_DrawList->CmdBuffer.Data + m_DrawListCommadBufferSize);
else if (m_DrawList->CmdBuffer.size() >= m_DrawListCommadBufferSize && m_DrawList->CmdBuffer[m_DrawListCommadBufferSize - 1].UserCallback == ImDrawCallback_ImCanvas)
m_DrawList->CmdBuffer.erase(m_DrawList->CmdBuffer.Data + m_DrawListCommadBufferSize - 1);
}
auto& fringeScale = ImFringeScaleRef(m_DrawList);
fringeScale = m_LastFringeScale;
// And pop \o/
ImGui::PopClipRect();
RestoreInputState();
RestoreViewportState();
}