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 "tools/viewer/ImGuiLayer.h"
9
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkImage.h"
12 #include "include/core/SkPixmap.h"
13 #include "include/core/SkSurface.h"
14 #include "include/core/SkSwizzle.h"
15 #include "include/core/SkTime.h"
16 #include "include/core/SkVertices.h"
17
18 #include "imgui.h"
19
20 #include <stdlib.h>
21 #include <map>
22
23 using namespace sk_app;
24
ImGuiLayer()25 ImGuiLayer::ImGuiLayer() {
26 // ImGui initialization:
27 ImGui::CreateContext();
28 ImGuiIO& io = ImGui::GetIO();
29
30 // Keymap...
31 io.KeyMap[ImGuiKey_Tab] = (int)skui::Key::kTab;
32 io.KeyMap[ImGuiKey_LeftArrow] = (int)skui::Key::kLeft;
33 io.KeyMap[ImGuiKey_RightArrow] = (int)skui::Key::kRight;
34 io.KeyMap[ImGuiKey_UpArrow] = (int)skui::Key::kUp;
35 io.KeyMap[ImGuiKey_DownArrow] = (int)skui::Key::kDown;
36 io.KeyMap[ImGuiKey_PageUp] = (int)skui::Key::kPageUp;
37 io.KeyMap[ImGuiKey_PageDown] = (int)skui::Key::kPageDown;
38 io.KeyMap[ImGuiKey_Home] = (int)skui::Key::kHome;
39 io.KeyMap[ImGuiKey_End] = (int)skui::Key::kEnd;
40 io.KeyMap[ImGuiKey_Delete] = (int)skui::Key::kDelete;
41 io.KeyMap[ImGuiKey_Backspace] = (int)skui::Key::kBack;
42 io.KeyMap[ImGuiKey_Enter] = (int)skui::Key::kOK;
43 io.KeyMap[ImGuiKey_Escape] = (int)skui::Key::kEscape;
44 io.KeyMap[ImGuiKey_A] = (int)skui::Key::kA;
45 io.KeyMap[ImGuiKey_C] = (int)skui::Key::kC;
46 io.KeyMap[ImGuiKey_V] = (int)skui::Key::kV;
47 io.KeyMap[ImGuiKey_X] = (int)skui::Key::kX;
48 io.KeyMap[ImGuiKey_Y] = (int)skui::Key::kY;
49 io.KeyMap[ImGuiKey_Z] = (int)skui::Key::kZ;
50
51 int w, h;
52 unsigned char* pixels;
53 io.Fonts->GetTexDataAsAlpha8(&pixels, &w, &h);
54 SkImageInfo info = SkImageInfo::MakeA8(w, h);
55 SkPixmap pmap(info, pixels, info.minRowBytes());
56 SkMatrix localMatrix = SkMatrix::MakeScale(1.0f / w, 1.0f / h);
57 auto fontImage = SkImage::MakeFromRaster(pmap, nullptr, nullptr);
58 auto fontShader = fontImage->makeShader(&localMatrix);
59 fFontPaint.setShader(fontShader);
60 fFontPaint.setColor(SK_ColorWHITE);
61 fFontPaint.setFilterQuality(kLow_SkFilterQuality);
62 io.Fonts->TexID = &fFontPaint;
63 }
64
~ImGuiLayer()65 ImGuiLayer::~ImGuiLayer() {
66 ImGui::DestroyContext();
67 }
68
onAttach(Window * window)69 void ImGuiLayer::onAttach(Window* window) {
70 fWindow = window;
71 }
72
onMouse(int x,int y,skui::InputState state,skui::ModifierKey modifiers)73 bool ImGuiLayer::onMouse(int x, int y, skui::InputState state, skui::ModifierKey modifiers) {
74 ImGuiIO& io = ImGui::GetIO();
75 io.MousePos.x = static_cast<float>(x);
76 io.MousePos.y = static_cast<float>(y);
77 if (skui::InputState::kDown == state) {
78 io.MouseDown[0] = true;
79 } else if (skui::InputState::kUp == state) {
80 io.MouseDown[0] = false;
81 }
82 return io.WantCaptureMouse;
83 }
84
onMouseWheel(float delta,skui::ModifierKey modifiers)85 bool ImGuiLayer::onMouseWheel(float delta, skui::ModifierKey modifiers) {
86 ImGuiIO& io = ImGui::GetIO();
87 io.MouseWheel += delta;
88 return true;
89 }
90
skiaWidget(const ImVec2 & size,SkiaWidgetFunc func)91 void ImGuiLayer::skiaWidget(const ImVec2& size, SkiaWidgetFunc func) {
92 intptr_t funcIndex = fSkiaWidgetFuncs.count();
93 fSkiaWidgetFuncs.push_back(func);
94 ImGui::Image((ImTextureID)funcIndex, size);
95 }
96
onPrePaint()97 void ImGuiLayer::onPrePaint() {
98 // Update ImGui input
99 ImGuiIO& io = ImGui::GetIO();
100
101 static double previousTime = 0.0;
102 double currentTime = SkTime::GetSecs();
103 io.DeltaTime = static_cast<float>(currentTime - previousTime);
104 previousTime = currentTime;
105
106 io.DisplaySize.x = static_cast<float>(fWindow->width());
107 io.DisplaySize.y = static_cast<float>(fWindow->height());
108
109 io.KeyAlt = io.KeysDown[static_cast<int>(skui::Key::kOption)];
110 io.KeyCtrl = io.KeysDown[static_cast<int>(skui::Key::kCtrl)];
111 io.KeyShift = io.KeysDown[static_cast<int>(skui::Key::kShift)];
112
113 ImGui::NewFrame();
114 }
115
onPaint(SkSurface * surface)116 void ImGuiLayer::onPaint(SkSurface* surface) {
117 // This causes ImGui to rebuild vertex/index data based on all immediate-mode commands
118 // (widgets, etc...) that have been issued
119 ImGui::Render();
120
121 // Then we fetch the most recent data, and convert it so we can render with Skia
122 const ImDrawData* drawData = ImGui::GetDrawData();
123 SkTDArray<SkPoint> pos;
124 SkTDArray<SkPoint> uv;
125 SkTDArray<SkColor> color;
126
127 auto canvas = surface->getCanvas();
128
129 for (int i = 0; i < drawData->CmdListsCount; ++i) {
130 const ImDrawList* drawList = drawData->CmdLists[i];
131
132 // De-interleave all vertex data (sigh), convert to Skia types
133 pos.rewind(); uv.rewind(); color.rewind();
134 for (int j = 0; j < drawList->VtxBuffer.size(); ++j) {
135 const ImDrawVert& vert = drawList->VtxBuffer[j];
136 pos.push_back(SkPoint::Make(vert.pos.x, vert.pos.y));
137 uv.push_back(SkPoint::Make(vert.uv.x, vert.uv.y));
138 color.push_back(vert.col);
139 }
140 // ImGui colors are RGBA
141 SkSwapRB(color.begin(), color.begin(), color.count());
142
143 int indexOffset = 0;
144
145 // Draw everything with canvas.drawVertices...
146 for (int j = 0; j < drawList->CmdBuffer.size(); ++j) {
147 const ImDrawCmd* drawCmd = &drawList->CmdBuffer[j];
148
149 SkAutoCanvasRestore acr(canvas, true);
150
151 // TODO: Find min/max index for each draw, so we know how many vertices (sigh)
152 if (drawCmd->UserCallback) {
153 drawCmd->UserCallback(drawList, drawCmd);
154 } else {
155 intptr_t idIndex = (intptr_t)drawCmd->TextureId;
156 if (idIndex < fSkiaWidgetFuncs.count()) {
157 // Small image IDs are actually indices into a list of callbacks. We directly
158 // examing the vertex data to deduce the image rectangle, then reconfigure the
159 // canvas to be clipped and translated so that the callback code gets to use
160 // Skia to render a widget in the middle of an ImGui panel.
161 ImDrawIdx rectIndex = drawList->IdxBuffer[indexOffset];
162 SkPoint tl = pos[rectIndex], br = pos[rectIndex + 2];
163 canvas->clipRect(SkRect::MakeLTRB(tl.fX, tl.fY, br.fX, br.fY));
164 canvas->translate(tl.fX, tl.fY);
165 fSkiaWidgetFuncs[idIndex](canvas);
166 } else {
167 SkPaint* paint = static_cast<SkPaint*>(drawCmd->TextureId);
168 SkASSERT(paint);
169
170 canvas->clipRect(SkRect::MakeLTRB(drawCmd->ClipRect.x, drawCmd->ClipRect.y,
171 drawCmd->ClipRect.z, drawCmd->ClipRect.w));
172 auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
173 drawList->VtxBuffer.size(),
174 pos.begin(), uv.begin(), color.begin(),
175 drawCmd->ElemCount,
176 drawList->IdxBuffer.begin() + indexOffset);
177 canvas->drawVertices(vertices, SkBlendMode::kModulate, *paint);
178 }
179 indexOffset += drawCmd->ElemCount;
180 }
181 }
182 }
183
184 fSkiaWidgetFuncs.reset();
185 }
186
onKey(skui::Key key,skui::InputState state,skui::ModifierKey modifiers)187 bool ImGuiLayer::onKey(skui::Key key, skui::InputState state, skui::ModifierKey modifiers) {
188 ImGuiIO& io = ImGui::GetIO();
189 io.KeysDown[static_cast<int>(key)] = (skui::InputState::kDown == state);
190 return io.WantCaptureKeyboard;
191 }
192
onChar(SkUnichar c,skui::ModifierKey modifiers)193 bool ImGuiLayer::onChar(SkUnichar c, skui::ModifierKey modifiers) {
194 ImGuiIO& io = ImGui::GetIO();
195 if (io.WantTextInput) {
196 if (c > 0 && c < 0x10000) {
197 io.AddInputCharacter(c);
198 }
199 return true;
200 }
201 return false;
202 }
203