Moved the optional "courtesy maths operators" (#define IMGUI_DEFINE_MATH_OPERATORS) implementation from imgui_internal.h in imgui.h. (#6164, #6137, #5966, #2832)
@ -25,7 +25,8 @@ or view this file with any Markdown viewer.
| **Q&A: Usage** |
| **[About the ID Stack system..<br>Why is my widget not reacting when I click on it?<br>How can I have widgets with an empty label?<br>How can I have multiple widgets with the same label?<br>How can I have multiple windows with the same label?](#q-about-the-id-stack-system)** |
| [How can I display an image? What is ImTextureID, how does it work?](#q-how-can-i-display-an-image-what-is-imtextureid-how-does-it-work)|
| [How can I use my own math types instead of ImVec2/ImVec4?](#q-how-can-i-use-my-own-math-types-instead-of-imvec2imvec4) |
| [How can I use maths operators with ImVec2?](#q-how-can-i-use-maths-operators-with-imvec2) |
| [How can I use my own maths types instead of ImVec2/ImVec4?](#q-how-can-i-use-my-own-maths-types-instead-of-imvec2imvec4) |
| [How can I interact with standard C++ types (such as std::string and std::vector)?](#q-how-can-i-interact-with-standard-c-types-such-as-stdstring-and-stdvector) |
| [How can I display custom shapes? (using low-level ImDrawList API)](#q-how-can-i-display-custom-shapes-using-low-level-imdrawlist-api) |
| **Q&A: Fonts, Text** |
@ -426,10 +427,18 @@ Finally, you may call `ImGui::ShowMetricsWindow()` to explore/visualize/understa
---
### Q: How can I use my own math types instead of ImVec2/ImVec4?
### Q: How can I use maths operators with ImVec2?
You can edit [imconfig.h](https://github.com/ocornut/imgui/blob/master/imconfig.h) and setup the `IM_VEC2_CLASS_EXTRA`/`IM_VEC4_CLASS_EXTRA` macros to add implicit type conversions.
This way you'll be able to use your own types everywhere, e.g. passing `MyVector2` or `glm::vec2` to ImGui functions instead of `ImVec2`.
We do not export maths operators by default in imgui.h in order to not conflict with the use of your own maths types and maths operators. As a convenience, you may use `#defne IMGUI_DEFINE_MATH_OPERATORS` + `#include "imgui.h"` to access our basic maths operators.
##### [Return to Index](#index)
---
### Q: How can I use my own maths types instead of ImVec2/ImVec4?
You can setup your [imconfig.h](https://github.com/ocornut/imgui/blob/master/imconfig.h) file with `IM_VEC2_CLASS_EXTRA`/`IM_VEC4_CLASS_EXTRA` macros to add implicit type conversions to our own maths types.
This way you will be able to use your own types everywhere, e.g. passing `MyVector2` or `glm::vec2` to ImGui functions instead of `ImVec2`.
##### [Return to Index](#index)
@ -485,7 +494,7 @@ ImGui::End();
- Refer to "Demo > Examples > Custom Rendering" in the demo window and read the code of `ShowExampleAppCustomRendering()` in `imgui_demo.cpp` from more examples.
- To generate colors: you can use the macro `IM_COL32(255,255,255,255)` to generate them at compile time, or use `ImGui::GetColorU32(IM_COL32(255,255,255,255))` or `ImGui::GetColorU32(ImVec4(1.0f,1.0f,1.0f,1.0f))` to generate a color that is multiplied by the current value of `style.Alpha`.
- Math operators: if you have setup `IM_VEC2_CLASS_EXTRA` in `imconfig.h` to bind your own math types, you can use your own math types and their natural operators instead of ImVec2. ImVec2 by default doesn't export any math operators in the public API. You may use `#define IMGUI_DEFINE_MATH_OPERATORS``#include "imgui_internal.h"` to use the internally defined math operators, but instead prefer using your own math library and set it up in `imconfig.h`.
- Math operators: if you have setup `IM_VEC2_CLASS_EXTRA` in `imconfig.h` to bind your own math types, you can use your own math types and their natural operators instead of ImVec2. ImVec2 by default doesn't export any math operators in the public API. You may use `#define IMGUI_DEFINE_MATH_OPERATORS``#include "imgui.h"` to use our math operators, but instead prefer using your own math library and set it up in `imconfig.h`.
- You can use `ImGui::GetBackgroundDrawList()` or `ImGui::GetForegroundDrawList()` to access draw lists which will be displayed behind and over every other Dear ImGui window (one bg/fg drawlist per viewport). This is very convenient if you need to quickly display something on the screen that is not associated with a Dear ImGui window.
- You can also create your own empty window and draw inside it. Call Begin() with the NoBackground | NoDecoration | NoSavedSettings | NoInputs flags (The `ImGuiWindowFlags_NoDecoration` flag itself is a shortcut for NoTitleBar | NoResize | NoScrollbar | NoCollapse). Then you can retrieve the ImDrawList* via `GetWindowDrawList()` and draw to it in any way you like.
- You can create your own ImDrawList instance. You'll need to initialize them with `ImGui::GetDrawListSharedData()`, or create your own instancing `ImDrawListSharedData`, and then call your renderer function with your own ImDrawList or ImDrawData data.
// - It is important that we are keeping those disabled by default so they don't leak in user space.
// - This is in order to allow user enabling implicit cast operators between ImVec2/ImVec4 and their own types (using IM_VEC2_CLASS_EXTRA in imconfig.h)
// - You can use '#define IMGUI_DEFINE_MATH_OPERATORS' to import our operators, provided as a courtesy.
// - We unfortunately don't have a unary- operator for ImVec2 because this would needs to be defined inside the class itself.
#pragma GCC diagnostic ignored "-Wclass-memaccess" // [__GNUC__ >= 8] warning: 'memset/memcpy' clearing/writing an object of type 'xxxx' with no trivial copy-assignment; use assignment or value-initialization instead
#endif
// In 1.89.4, we moved the implementation of "courtesy maths operators" from imgui_internal.h in imgui.h
// As they are frequently requested, we do not want to encourage to many people using imgui_internal.h
IMGUI_APIintImTextCountUtf8BytesFromChar(constchar*in_text,constchar*in_text_end);// return number of bytes to express one char in UTF-8
IMGUI_APIintImTextCountUtf8BytesFromStr(constImWchar*in_text,constImWchar*in_text_end);// return number of bytes to express string in UTF-8
// Helpers: ImVec2/ImVec4 operators
// We are keeping those disabled by default so they don't leak in user space, to allow user enabling implicit cast operators between ImVec2 and their own types (using IM_VEC2_CLASS_EXTRA etc.)
// We unfortunately don't have a unary- operator for ImVec2 because this would needs to be defined inside the class itself.
ocornut
2 years ago