Merge pull request livecode#6337 from montegoulding/feature-my_pixel_scale

livecodeali · web-flow · commit a8288939ccb4 · 2018-02-20T15:26:45.000Z
[[ MyPixelScale ]] Implement my pixel scale expression
diff --git a/docs/lcb/notes/feature-my_pixel_scale.md b/docs/lcb/notes/feature-my_pixel_scale.md
@@ -0,0 +1,9 @@
+# LiveCode Builder Host Library
+## Widget library
+
+A new expression `my pixel scale` has been implemented. Use the widget's
+pixel scale to calculate the size of an image to draw. For example,
+when drawing an image to `my bounds` create an image sized using
+`my width * my pixel scale, my height * my pixel scale` otherwise the image will be
+stretched to match the pixel scale. The pixel scale is a per-window/screen property
+so may change if the user moves a window to a new screen.
diff --git a/engine/src/widget-syntax.cpp b/engine/src/widget-syntax.cpp
@@ -316,6 +316,14 @@ extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMyPaint(uinteger_t p_type, MCCanvasP
     MCCanvasSolidPaintMakeWithColor(kMCCanvasColorBlack, (MCCanvasSolidPaintRef&)r_paint);
 }
 
+extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMyPixelScale(MCCanvasFloat& r_pixel_scale)
+{
+    if (!MCWidgetEnsureCurrentWidget())
+        return;
+    
+    r_pixel_scale = MCWidgetGetHost(MCcurrentwidget)->getstack()->view_getbackingscale();
+}
+
 extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMousePosition(bool p_current, MCCanvasPointRef& r_point)
 {
     if (!MCWidgetEnsureCurrentWidget())
diff --git a/engine/src/widget.lcb b/engine/src/widget.lcb
@@ -520,6 +520,7 @@ public foreign handler MCWidgetGetMyFont(out rFont as Font) returns nothing bind
 public foreign handler MCWidgetGetMyEnabled(out rEnabled as CBool) returns nothing binds to "<builtin>"
 public foreign handler MCWidgetGetMyDisabled(out rDisabled as CBool) returns nothing binds to "<builtin>"
 public foreign handler MCWidgetGetMyPaint(in pPaintType as CUInt, out rPaint as Paint) returns nothing binds to "<builtin>"
+public foreign handler MCWidgetGetMyPixelScale(out rPixelScale as CanvasFloat) returns nothing binds to "<builtin>"
 
 /**
 Summary:	Returns the widget script object.
@@ -654,6 +655,24 @@ begin
     MCWidgetGetMyPaint(mPaintType, output)
 end syntax
 
+/**
+Summary:    Returns the scaling factor of pixels for the widget
+
+Description:
+Use the widget's pixel scale to calculate the size of an image to draw. For example,
+when drawing an image to `my bounds` create an image sized using
+`my width * my pixel scale, my height * my pixel scale` otherwise the image will be
+stretched to match the pixel scale. The pixel scale is a per-window/screen property
+so may change if the user moves a window to a new screen.
+
+Returns:    The current scaling factor of pixels for the widget
+*/
+syntax MyPixelScale is expression
+    "my" "pixel" "scale"
+begin
+    MCWidgetGetMyPixelScale(output)
+end syntax
+
 // ---------- Synchronous and asynchronous ("current") event information ---------- //
 
 //foreign type PressedState binds to "MCPressedState"

Original file line number	Diff line number	Diff line change
`@@ -316,6 +316,14 @@ extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMyPaint(uinteger_t p_type, MCCanvasP`
`316`	`316`	`MCCanvasSolidPaintMakeWithColor(kMCCanvasColorBlack, (MCCanvasSolidPaintRef&)r_paint);`
`317`	`317`	`}`
`318`	`318`
	`319`	`+extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMyPixelScale(MCCanvasFloat& r_pixel_scale)`
	`320`	`+{`
	`321`	`+ if (!MCWidgetEnsureCurrentWidget())`
	`322`	`+ return;`
	`323`	`+`
	`324`	`+ r_pixel_scale = MCWidgetGetHost(MCcurrentwidget)->getstack()->view_getbackingscale();`
	`325`	`+}`
	`326`	`+`
`319`	`327`	`extern "C" MC_DLLEXPORT_DEF void MCWidgetGetMousePosition(bool p_current, MCCanvasPointRef& r_point)`
`320`	`328`	`{`
`321`	`329`	`if (!MCWidgetEnsureCurrentWidget())`