skia2/tools/viewer/ImGuiLayer.cpp

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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "ImGuiLayer.h"
#include "SkCanvas.h"
#include "SkImage.h"
#include "SkPixmap.h"
#include "SkSwizzle.h"
#include "SkVertices.h"
#include "imgui.h"
#include <stdlib.h>
#include <map>
using namespace sk_app;
ImGuiLayer::ImGuiLayer() {
// ImGui initialization:
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO();
// Keymap...
io.KeyMap[ImGuiKey_Tab] = (int)Window::Key::kTab;
io.KeyMap[ImGuiKey_LeftArrow] = (int)Window::Key::kLeft;
io.KeyMap[ImGuiKey_RightArrow] = (int)Window::Key::kRight;
io.KeyMap[ImGuiKey_UpArrow] = (int)Window::Key::kUp;
io.KeyMap[ImGuiKey_DownArrow] = (int)Window::Key::kDown;
io.KeyMap[ImGuiKey_PageUp] = (int)Window::Key::kPageUp;
io.KeyMap[ImGuiKey_PageDown] = (int)Window::Key::kPageDown;
io.KeyMap[ImGuiKey_Home] = (int)Window::Key::kHome;
io.KeyMap[ImGuiKey_End] = (int)Window::Key::kEnd;
io.KeyMap[ImGuiKey_Delete] = (int)Window::Key::kDelete;
io.KeyMap[ImGuiKey_Backspace] = (int)Window::Key::kBack;
io.KeyMap[ImGuiKey_Enter] = (int)Window::Key::kOK;
io.KeyMap[ImGuiKey_Escape] = (int)Window::Key::kEscape;
io.KeyMap[ImGuiKey_A] = (int)Window::Key::kA;
io.KeyMap[ImGuiKey_C] = (int)Window::Key::kC;
io.KeyMap[ImGuiKey_V] = (int)Window::Key::kV;
io.KeyMap[ImGuiKey_X] = (int)Window::Key::kX;
io.KeyMap[ImGuiKey_Y] = (int)Window::Key::kY;
io.KeyMap[ImGuiKey_Z] = (int)Window::Key::kZ;
int w, h;
unsigned char* pixels;
io.Fonts->GetTexDataAsAlpha8(&pixels, &w, &h);
SkImageInfo info = SkImageInfo::MakeA8(w, h);
SkPixmap pmap(info, pixels, info.minRowBytes());
SkMatrix localMatrix = SkMatrix::MakeScale(1.0f / w, 1.0f / h);
auto fontImage = SkImage::MakeFromRaster(pmap, nullptr, nullptr);
auto fontShader = fontImage->makeShader(&localMatrix);
fFontPaint.setShader(fontShader);
fFontPaint.setColor(SK_ColorWHITE);
fFontPaint.setFilterQuality(kLow_SkFilterQuality);
io.Fonts->TexID = &fFontPaint;
}
ImGuiLayer::~ImGuiLayer() {
ImGui::DestroyContext();
}
void ImGuiLayer::onAttach(Window* window) {
fWindow = window;
}
bool ImGuiLayer::onMouse(int x, int y, Window::InputState state, uint32_t modifiers) {
ImGuiIO& io = ImGui::GetIO();
io.MousePos.x = static_cast<float>(x);
io.MousePos.y = static_cast<float>(y);
if (Window::kDown_InputState == state) {
io.MouseDown[0] = true;
} else if (Window::kUp_InputState == state) {
io.MouseDown[0] = false;
}
return io.WantCaptureMouse;
}
bool ImGuiLayer::onMouseWheel(float delta, uint32_t modifiers) {
ImGuiIO& io = ImGui::GetIO();
io.MouseWheel += delta;
return true;
}
void ImGuiLayer::skiaWidget(const ImVec2& size, SkiaWidgetFunc func) {
intptr_t funcIndex = fSkiaWidgetFuncs.count();
fSkiaWidgetFuncs.push_back(func);
ImGui::Image((ImTextureID)funcIndex, size);
}
void ImGuiLayer::onPrePaint() {
// Update ImGui input
ImGuiIO& io = ImGui::GetIO();
io.DeltaTime = 1.0f / 60.0f;
io.DisplaySize.x = static_cast<float>(fWindow->width());
io.DisplaySize.y = static_cast<float>(fWindow->height());
io.KeyAlt = io.KeysDown[static_cast<int>(Window::Key::kOption)];
io.KeyCtrl = io.KeysDown[static_cast<int>(Window::Key::kCtrl)];
io.KeyShift = io.KeysDown[static_cast<int>(Window::Key::kShift)];
ImGui::NewFrame();
}
void ImGuiLayer::onPaint(SkCanvas* canvas) {
// This causes ImGui to rebuild vertex/index data based on all immediate-mode commands
// (widgets, etc...) that have been issued
ImGui::Render();
// Then we fetch the most recent data, and convert it so we can render with Skia
const ImDrawData* drawData = ImGui::GetDrawData();
SkTDArray<SkPoint> pos;
SkTDArray<SkPoint> uv;
SkTDArray<SkColor> color;
for (int i = 0; i < drawData->CmdListsCount; ++i) {
const ImDrawList* drawList = drawData->CmdLists[i];
// De-interleave all vertex data (sigh), convert to Skia types
pos.rewind(); uv.rewind(); color.rewind();
for (int j = 0; j < drawList->VtxBuffer.size(); ++j) {
const ImDrawVert& vert = drawList->VtxBuffer[j];
pos.push_back(SkPoint::Make(vert.pos.x, vert.pos.y));
uv.push_back(SkPoint::Make(vert.uv.x, vert.uv.y));
color.push_back(vert.col);
}
// ImGui colors are RGBA
SkSwapRB(color.begin(), color.begin(), color.count());
int indexOffset = 0;
// Draw everything with canvas.drawVertices...
for (int j = 0; j < drawList->CmdBuffer.size(); ++j) {
const ImDrawCmd* drawCmd = &drawList->CmdBuffer[j];
SkAutoCanvasRestore acr(canvas, true);
// TODO: Find min/max index for each draw, so we know how many vertices (sigh)
if (drawCmd->UserCallback) {
drawCmd->UserCallback(drawList, drawCmd);
} else {
intptr_t idIndex = (intptr_t)drawCmd->TextureId;
if (idIndex < fSkiaWidgetFuncs.count()) {
// Small image IDs are actually indices into a list of callbacks. We directly
// examing the vertex data to deduce the image rectangle, then reconfigure the
// canvas to be clipped and translated so that the callback code gets to use
// Skia to render a widget in the middle of an ImGui panel.
ImDrawIdx rectIndex = drawList->IdxBuffer[indexOffset];
SkPoint tl = pos[rectIndex], br = pos[rectIndex + 2];
canvas->clipRect(SkRect::MakeLTRB(tl.fX, tl.fY, br.fX, br.fY));
canvas->translate(tl.fX, tl.fY);
fSkiaWidgetFuncs[idIndex](canvas);
} else {
SkPaint* paint = static_cast<SkPaint*>(drawCmd->TextureId);
SkASSERT(paint);
canvas->clipRect(SkRect::MakeLTRB(drawCmd->ClipRect.x, drawCmd->ClipRect.y,
drawCmd->ClipRect.z, drawCmd->ClipRect.w));
auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
drawList->VtxBuffer.size(),
pos.begin(), uv.begin(), color.begin(),
drawCmd->ElemCount,
drawList->IdxBuffer.begin() + indexOffset);
canvas->drawVertices(vertices, SkBlendMode::kModulate, *paint);
indexOffset += drawCmd->ElemCount;
}
}
}
}
fSkiaWidgetFuncs.reset();
}
bool ImGuiLayer::onKey(sk_app::Window::Key key, sk_app::Window::InputState state, uint32_t modifiers) {
ImGuiIO& io = ImGui::GetIO();
io.KeysDown[static_cast<int>(key)] = (Window::kDown_InputState == state);
return io.WantCaptureKeyboard;
}
bool ImGuiLayer::onChar(SkUnichar c, uint32_t modifiers) {
ImGuiIO& io = ImGui::GetIO();
if (io.WantTextInput) {
if (c > 0 && c < 0x10000) {
io.AddInputCharacter(c);
}
return true;
}
return false;
}