Turn on type conversion warnings for GCC and fix them.

4 files changed, 16 insertions, 14 deletions

diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 02f31cc5e..ff47c28ab 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -168,7 +168,7 @@ float GetDeviceScaleFactorWhenGdiScalingActive(HWND hWnd) noexcept {
 			const HMONITOR hMonitor = MonitorFromWindowHandleScaling(hRootWnd);
 			DEVICE_SCALE_FACTOR deviceScaleFactor;
 			if (S_OK == fnGetScaleFactorForMonitor(hMonitor, &deviceScaleFactor))
-				return static_cast<int>(deviceScaleFactor) / 100.f;
+				return static_cast<float>(static_cast<int>(deviceScaleFactor)) / 100.f;
 		}
 	}
 	return 1.f;
@@ -404,6 +404,8 @@ class CursorHelper {
 	DWORD *pixels = nullptr;
 	const int width;
 	const int height;
+	const float scale;
+	static constexpr float baseSize = 32.0f;
 
 	static constexpr float arrow[][2] = {
 		{ 32.0f - 12.73606f,32.0f - 19.04075f },
@@ -418,7 +420,7 @@ class CursorHelper {
 public:
 	~CursorHelper() = default;
 
-	CursorHelper(int width_, int height_) noexcept : width{width_}, height{height_} {
+	CursorHelper(int width_, int height_) noexcept : width{width_}, height{height_}, scale{ static_cast<float>(width) / baseSize } {
 		// https://learn.microsoft.com/en-us/windows/win32/menurc/using-cursors#creating-a-cursor
 		bm.Create({}, width, height, &pixels);
 	}
@@ -470,7 +472,6 @@ public:
 		// Draw something on the bitmap section.
 		constexpr size_t nPoints = std::size(arrow);
 		D2D1_POINT_2F points[nPoints]{};
-		const FLOAT scale = width/32.0f;
 		for (size_t i = 0; i < nPoints; i++) {
 			points[i].x = arrow[i][0] * scale;
 			points[i].y = arrow[i][1] * scale;
@@ -519,7 +520,6 @@ public:
 		// Draw something on the DIB section.
 		constexpr size_t nPoints = std::size(arrow);
 		POINT points[nPoints]{};
-		const float scale = width/32.0f;
 		for (size_t i = 0; i < nPoints; i++) {
 			points[i].x = std::lround(arrow[i][0] * scale);
 			points[i].y = std::lround(arrow[i][1] * scale);
diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index d6ae32736..f31d1291f 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -874,7 +874,7 @@ void ScintillaWin::CreateRenderTarget() {
 		const RECT rc = GetClientRect(hw);
 
 		const int integralDeviceScaleFactor = GetFirstIntegralMultipleDeviceScaleFactor();
-		const FLOAT dpiTarget = dpiDefault * integralDeviceScaleFactor;
+		const FLOAT dpiTarget = dpiDefault * static_cast<float>(integralDeviceScaleFactor);
 
 		const D2D1_RENDER_TARGET_PROPERTIES drtp = D2D1::RenderTargetProperties(
 			D2D1_RENDER_TARGET_TYPE_DEFAULT,
@@ -1009,7 +1009,7 @@ void ScintillaWin::DisplayCursor(Window::Cursor c) {
 		c = static_cast<Window::Cursor>(cursorMode);
 	}
 	if (c == Window::Cursor::reverseArrow) {
-		::SetCursor(reverseArrowCursor.Load(static_cast<UINT>(dpi * deviceScaleFactor)));
+		::SetCursor(reverseArrowCursor.Load(static_cast<UINT>(static_cast<float>(dpi) * deviceScaleFactor)));
 	} else {
 		wMain.SetCursor(c);
 	}
@@ -2809,11 +2809,11 @@ constexpr int minTrailByte = 0x30;
 
 // CreateFoldMap creates a fold map by calling platform APIs so will differ between platforms.
 void CreateFoldMap(int codePage, FoldMap *foldingMap) {
-	for (int byte1 = highByteFirst; byte1 <= highByteLast; byte1++) {
-		const char ch1 = byte1 & 0xFF;	// & 0xFF avoids warnings but has no real effect.
+	for (unsigned char byte1 = highByteLast; byte1 >= highByteFirst; byte1--) {
+		const char ch1 = byte1;
 		if (DBCSIsLeadByte(codePage, ch1)) {
-			for (int byte2 = minTrailByte; byte2 <= highByteLast; byte2++) {
-				const char ch2 = byte2 & 0xFF;
+			for (unsigned char byte2 = highByteLast; byte2 >= minTrailByte; byte2--) {
+				const char ch2 = byte2;
 				if (DBCSIsTrailByte(codePage, ch2)) {
 					const DBCSPair pair{ ch1, ch2 };
 					const uint16_t index = DBCSIndex(ch1, ch2);
@@ -3426,8 +3426,8 @@ LRESULT ScintillaWin::ImeOnReconvert(LPARAM lParam) {
 		return 0;
 
 	// No selection asks IME to fill target fields with its own value.
-	const int tgWlen = rc->dwTargetStrLen;
-	const int tgWstart = rc->dwTargetStrOffset / sizeof(wchar_t);
+	const size_t tgWlen = rc->dwTargetStrLen;
+	const size_t tgWstart = rc->dwTargetStrOffset / sizeof(wchar_t);
 
 	std::string tgCompStart = StringEncode(rcFeed.substr(0, tgWstart), codePage);
 	std::string tgComp = StringEncode(rcFeed.substr(tgWstart, tgWlen), codePage);
@@ -3945,7 +3945,7 @@ void ScintillaWin::CTPaint(HWND hWnd) {
 
 		// Create a Direct2D render target.
 
-		const FLOAT dpiTarget = dpiDefault * scaleFactor;
+		const FLOAT dpiTarget = dpiDefault * static_cast<float>(scaleFactor);
 
 		const D2D1_RENDER_TARGET_PROPERTIES drtp = D2D1::RenderTargetProperties(
 			D2D1_RENDER_TARGET_TYPE_DEFAULT,
diff --git a/win32/SurfaceD2D.cxx b/win32/SurfaceD2D.cxx
index fa8383a84..223d35fcf 100644
--- a/win32/SurfaceD2D.cxx
+++ b/win32/SurfaceD2D.cxx
@@ -1382,7 +1382,8 @@ HRESULT MeasurePositions(TextPositions &poses, const TextWide &tbuf, IDWriteText
 	int ti=0;
 	for (unsigned int ci=0; ci<count; ci++) {
 		for (unsigned int inCluster=0; inCluster<clusterMetrics[ci].length; inCluster++) {
-			poses.buffer[ti++] = position + clusterMetrics[ci].width * (inCluster + 1) / clusterMetrics[ci].length;
+			const float proportion = static_cast<float>(inCluster + 1) / clusterMetrics[ci].length;
+			poses.buffer[ti++] = position + clusterMetrics[ci].width * proportion;
 		}
 		position += clusterMetrics[ci].width;
 	}
diff --git a/win32/makefile b/win32/makefile
index 72634889f..5db9e6625 100644
--- a/win32/makefile
+++ b/win32/makefile
@@ -23,6 +23,7 @@ else
 # MinGW GCC
 LIBSMINGW = -lstdc++
 STRIPOPTION = -s
+WARNINGS += -Wconversion
 endif
 ARFLAGS = rc
 RANLIB ?= ranlib