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