From 495a7ac166ee3d7ee4bdc5768c66547724cb4562 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Mon, 23 Jan 2017 00:24:18 +0000
Subject: [PATCH] =?UTF-8?q?Refactor=20the=20"File=20=E2=86=92=20Export=20I?=
 =?UTF-8?q?mage"=20command.?=
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The existing code is horrible and needlessly platform-dependent.
Even worse, it causes a freeze on GTK. Instead of propping that up
with a few more crutches, just fix the root cause.
---
 src/CMakeLists.txt |  2 +-
 src/draw.cpp       | 34 +++++++++++++++++++++-------------
 src/export.cpp     | 35 ++---------------------------------
 src/solvespace.h   |  1 +
 4 files changed, 25 insertions(+), 47 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1d4d3ddc..45b475f5 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -154,6 +154,7 @@ set(solvespace_core_SOURCES
     drawconstraint.cpp
     drawentity.cpp
     entity.cpp
+    export.cpp
     exportstep.cpp
     exportvector.cpp
     expr.cpp
@@ -191,7 +192,6 @@ set(solvespace_core_SOURCES
     srf/triangulate.cpp)
 
 set(solvespace_core_gl_SOURCES
-    export.cpp
     solvespace.cpp)
 
 add_library(solvespace-core STATIC
diff --git a/src/draw.cpp b/src/draw.cpp
index b6776173..849c2484 100644
--- a/src/draw.cpp
+++ b/src/draw.cpp
@@ -885,26 +885,34 @@ void GraphicsWindow::Paint() {
                           /*outlineColor=*/Style::Color(Style::HOVERED));
     }
 
+    // If we've had a screenshot requested, take it now, before the UI is overlaid.
+    if(!SS.screenshotFile.empty()) {
+        FILE *f = ssfopen(SS.screenshotFile, "wb");
+        if(!f || !canvas->ReadFrame()->WritePng(f, /*flip=*/true)) {
+            Error("Couldn't write to '%s'", SS.screenshotFile.c_str());
+        }
+        if(f) fclose(f);
+        SS.screenshotFile.clear();
+    }
+
     // And finally the toolbar.
     if(SS.showToolbar) {
         canvas->SetCamera(camera);
         ToolbarDraw(&uiCanvas);
     }
 
-    // If we display UI elements, also display an fps counter.
-    if(SS.showToolbar) {
-        RgbaColor renderTimeColor;
-        if(1000 / renderTime.count() < 60) {
-            // We aim for a steady 60fps; draw the counter in red when we're slower.
-            renderTimeColor = { 255, 0, 0, 255 };
-        } else {
-            renderTimeColor = { 255, 255, 255, 255 };
-        }
-        uiCanvas.DrawBitmapText(ssprintf("rendered in %ld ms (%ld 1/s)",
-                                         (long)renderTime.count(),
-                                         (long)(1000/renderTime.count())),
-                                5, 5, renderTimeColor);
+    // Also display an fps counter.
+    RgbaColor renderTimeColor;
+    if(1000 / renderTime.count() < 60) {
+        // We aim for a steady 60fps; draw the counter in red when we're slower.
+        renderTimeColor = { 255, 0, 0, 255 };
+    } else {
+        renderTimeColor = { 255, 255, 255, 255 };
     }
+    uiCanvas.DrawBitmapText(ssprintf("rendered in %ld ms (%ld 1/s)",
+                                     (long)renderTime.count(),
+                                     (long)(1000/renderTime.count())),
+                            5, 5, renderTimeColor);
 
     canvas->FlushFrame();
     canvas->Clear();
diff --git a/src/export.cpp b/src/export.cpp
index 50f017cd..4c34811d 100644
--- a/src/export.cpp
+++ b/src/export.cpp
@@ -1117,39 +1117,8 @@ void SolveSpaceUI::ExportMeshAsThreeJsTo(FILE *f, const std::string &filename,
 // rendering the view in the usual way and then copying the pixels.
 //-----------------------------------------------------------------------------
 void SolveSpaceUI::ExportAsPngTo(const std::string &filename) {
-#if !defined(HEADLESS)
-    // No guarantee that the back buffer contains anything valid right now,
-    // so repaint the scene. And hide the toolbar too.
-    bool prevShowToolbar = SS.showToolbar;
-    SS.showToolbar = false;
-
-    // Somewhat hacky way to invoke glReadPixels without dragging in all OpenGL headers.
-    std::shared_ptr<ViewportCanvas> canvas = CreateRenderer();
-    canvas->SetCamera(SS.GW.GetCamera());
-    std::shared_ptr<Pixmap> screenshot;
-#if !defined(WIN32)
-    GlOffscreen offscreen;
-    offscreen.Render((int)SS.GW.width, (int)SS.GW.height, [&] {
-        SS.GW.Paint();
-        screenshot = canvas->ReadFrame();
-    });
-#else
+    screenshotFile = filename;
+    // The rest of the work is done in the next redraw.
     SS.GW.Paint();
-    screenshot = canvas->ReadFrame();
-#endif
-    SS.showToolbar = prevShowToolbar;
-
-    FILE *f = ssfopen(filename, "wb");
-    if(!f || !screenshot->WritePng(f, /*flip=*/true)) {
-        Error("Couldn't write to '%s'", filename.c_str());
-    }
-    if(f) fclose(f);
-
-#if !defined(WIN32)
-    offscreen.Clear();
-#endif
-
-    return;
-#endif
 }
 
diff --git a/src/solvespace.h b/src/solvespace.h
index 7468eed3..32a07e34 100644
--- a/src/solvespace.h
+++ b/src/solvespace.h
@@ -676,6 +676,7 @@ public:
     bool     drawBackFaces;
     bool     checkClosedContour;
     bool     showToolbar;
+    std::string screenshotFile;
     RgbaColor backgroundColor;
     bool     exportShadedTriangles;
     bool     exportPwlCurves;