1 /*
2 * Copyright 2017 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "ImGuiLayer.h"
9
10 #include "SkCanvas.h"
11 #include "SkImage.h"
12 #include "SkPixmap.h"
13 #include "SkSwizzle.h"
14 #include "SkVertices.h"
15
16 #include "imgui.h"
17
18 #include <stdlib.h>
19 #include <map>
20
21 using namespace sk_app;
22
ImGuiLayer()23 ImGuiLayer::ImGuiLayer() {
24 // ImGui initialization:
25 ImGui::CreateContext();
26 ImGuiIO& io = ImGui::GetIO();
27
28 // Keymap...
29 io.KeyMap[ImGuiKey_Tab] = (int)Window::Key::kTab;
30 io.KeyMap[ImGuiKey_LeftArrow] = (int)Window::Key::kLeft;
31 io.KeyMap[ImGuiKey_RightArrow] = (int)Window::Key::kRight;
32 io.KeyMap[ImGuiKey_UpArrow] = (int)Window::Key::kUp;
33 io.KeyMap[ImGuiKey_DownArrow] = (int)Window::Key::kDown;
34 io.KeyMap[ImGuiKey_PageUp] = (int)Window::Key::kPageUp;
35 io.KeyMap[ImGuiKey_PageDown] = (int)Window::Key::kPageDown;
36 io.KeyMap[ImGuiKey_Home] = (int)Window::Key::kHome;
37 io.KeyMap[ImGuiKey_End] = (int)Window::Key::kEnd;
38 io.KeyMap[ImGuiKey_Delete] = (int)Window::Key::kDelete;
39 io.KeyMap[ImGuiKey_Backspace] = (int)Window::Key::kBack;
40 io.KeyMap[ImGuiKey_Enter] = (int)Window::Key::kOK;
41 io.KeyMap[ImGuiKey_Escape] = (int)Window::Key::kEscape;
42 io.KeyMap[ImGuiKey_A] = (int)Window::Key::kA;
43 io.KeyMap[ImGuiKey_C] = (int)Window::Key::kC;
44 io.KeyMap[ImGuiKey_V] = (int)Window::Key::kV;
45 io.KeyMap[ImGuiKey_X] = (int)Window::Key::kX;
46 io.KeyMap[ImGuiKey_Y] = (int)Window::Key::kY;
47 io.KeyMap[ImGuiKey_Z] = (int)Window::Key::kZ;
48
49 int w, h;
50 unsigned char* pixels;
51 io.Fonts->GetTexDataAsAlpha8(&pixels, &w, &h);
52 SkImageInfo info = SkImageInfo::MakeA8(w, h);
53 SkPixmap pmap(info, pixels, info.minRowBytes());
54 SkMatrix localMatrix = SkMatrix::MakeScale(1.0f / w, 1.0f / h);
55 auto fontImage = SkImage::MakeFromRaster(pmap, nullptr, nullptr);
56 auto fontShader = fontImage->makeShader(&localMatrix);
57 fFontPaint.setShader(fontShader);
58 fFontPaint.setColor(SK_ColorWHITE);
59 fFontPaint.setFilterQuality(kLow_SkFilterQuality);
60 io.Fonts->TexID = &fFontPaint;
61 }
62
~ImGuiLayer()63 ImGuiLayer::~ImGuiLayer() {
64 ImGui::DestroyContext();
65 }
66
onAttach(Window * window)67 void ImGuiLayer::onAttach(Window* window) {
68 fWindow = window;
69 }
70
onMouse(int x,int y,Window::InputState state,uint32_t modifiers)71 bool ImGuiLayer::onMouse(int x, int y, Window::InputState state, uint32_t modifiers) {
72 ImGuiIO& io = ImGui::GetIO();
73 io.MousePos.x = static_cast<float>(x);
74 io.MousePos.y = static_cast<float>(y);
75 if (Window::kDown_InputState == state) {
76 io.MouseDown[0] = true;
77 } else if (Window::kUp_InputState == state) {
78 io.MouseDown[0] = false;
79 }
80 return io.WantCaptureMouse;
81 }
82
onMouseWheel(float delta,uint32_t modifiers)83 bool ImGuiLayer::onMouseWheel(float delta, uint32_t modifiers) {
84 ImGuiIO& io = ImGui::GetIO();
85 io.MouseWheel += delta;
86 return true;
87 }
88
skiaWidget(const ImVec2 & size,SkiaWidgetFunc func)89 void ImGuiLayer::skiaWidget(const ImVec2& size, SkiaWidgetFunc func) {
90 intptr_t funcIndex = fSkiaWidgetFuncs.count();
91 fSkiaWidgetFuncs.push_back(func);
92 ImGui::Image((ImTextureID)funcIndex, size);
93 }
94
onPrePaint()95 void ImGuiLayer::onPrePaint() {
96 // Update ImGui input
97 ImGuiIO& io = ImGui::GetIO();
98 io.DeltaTime = 1.0f / 60.0f;
99 io.DisplaySize.x = static_cast<float>(fWindow->width());
100 io.DisplaySize.y = static_cast<float>(fWindow->height());
101
102 io.KeyAlt = io.KeysDown[static_cast<int>(Window::Key::kOption)];
103 io.KeyCtrl = io.KeysDown[static_cast<int>(Window::Key::kCtrl)];
104 io.KeyShift = io.KeysDown[static_cast<int>(Window::Key::kShift)];
105
106 ImGui::NewFrame();
107 }
108
onPaint(SkCanvas * canvas)109 void ImGuiLayer::onPaint(SkCanvas* canvas) {
110 // This causes ImGui to rebuild vertex/index data based on all immediate-mode commands
111 // (widgets, etc...) that have been issued
112 ImGui::Render();
113
114 // Then we fetch the most recent data, and convert it so we can render with Skia
115 const ImDrawData* drawData = ImGui::GetDrawData();
116 SkTDArray<SkPoint> pos;
117 SkTDArray<SkPoint> uv;
118 SkTDArray<SkColor> color;
119
120 for (int i = 0; i < drawData->CmdListsCount; ++i) {
121 const ImDrawList* drawList = drawData->CmdLists[i];
122
123 // De-interleave all vertex data (sigh), convert to Skia types
124 pos.rewind(); uv.rewind(); color.rewind();
125 for (int j = 0; j < drawList->VtxBuffer.size(); ++j) {
126 const ImDrawVert& vert = drawList->VtxBuffer[j];
127 pos.push_back(SkPoint::Make(vert.pos.x, vert.pos.y));
128 uv.push_back(SkPoint::Make(vert.uv.x, vert.uv.y));
129 color.push_back(vert.col);
130 }
131 // ImGui colors are RGBA
132 SkSwapRB(color.begin(), color.begin(), color.count());
133
134 int indexOffset = 0;
135
136 // Draw everything with canvas.drawVertices...
137 for (int j = 0; j < drawList->CmdBuffer.size(); ++j) {
138 const ImDrawCmd* drawCmd = &drawList->CmdBuffer[j];
139
140 SkAutoCanvasRestore acr(canvas, true);
141
142 // TODO: Find min/max index for each draw, so we know how many vertices (sigh)
143 if (drawCmd->UserCallback) {
144 drawCmd->UserCallback(drawList, drawCmd);
145 } else {
146 intptr_t idIndex = (intptr_t)drawCmd->TextureId;
147 if (idIndex < fSkiaWidgetFuncs.count()) {
148 // Small image IDs are actually indices into a list of callbacks. We directly
149 // examing the vertex data to deduce the image rectangle, then reconfigure the
150 // canvas to be clipped and translated so that the callback code gets to use
151 // Skia to render a widget in the middle of an ImGui panel.
152 ImDrawIdx rectIndex = drawList->IdxBuffer[indexOffset];
153 SkPoint tl = pos[rectIndex], br = pos[rectIndex + 2];
154 canvas->clipRect(SkRect::MakeLTRB(tl.fX, tl.fY, br.fX, br.fY));
155 canvas->translate(tl.fX, tl.fY);
156 fSkiaWidgetFuncs[idIndex](canvas);
157 } else {
158 SkPaint* paint = static_cast<SkPaint*>(drawCmd->TextureId);
159 SkASSERT(paint);
160
161 canvas->clipRect(SkRect::MakeLTRB(drawCmd->ClipRect.x, drawCmd->ClipRect.y,
162 drawCmd->ClipRect.z, drawCmd->ClipRect.w));
163 auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
164 drawList->VtxBuffer.size(),
165 pos.begin(), uv.begin(), color.begin(),
166 drawCmd->ElemCount,
167 drawList->IdxBuffer.begin() + indexOffset);
168 canvas->drawVertices(vertices, SkBlendMode::kModulate, *paint);
169 indexOffset += drawCmd->ElemCount;
170 }
171 }
172 }
173 }
174
175 fSkiaWidgetFuncs.reset();
176 }
177
onKey(sk_app::Window::Key key,sk_app::Window::InputState state,uint32_t modifiers)178 bool ImGuiLayer::onKey(sk_app::Window::Key key, sk_app::Window::InputState state, uint32_t modifiers) {
179 ImGuiIO& io = ImGui::GetIO();
180 io.KeysDown[static_cast<int>(key)] = (Window::kDown_InputState == state);
181 return io.WantCaptureKeyboard;
182 }
183
onChar(SkUnichar c,uint32_t modifiers)184 bool ImGuiLayer::onChar(SkUnichar c, uint32_t modifiers) {
185 ImGuiIO& io = ImGui::GetIO();
186 if (io.WantTextInput) {
187 if (c > 0 && c < 0x10000) {
188 io.AddInputCharacter(c);
189 }
190 return true;
191 }
192 return false;
193 }
194