cefpython/src/client_handler/dpi_aware.cpp at cefpython57 · pythonthings/cefpython · GitHub

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// Project website: https://github.com/cztomczak/cefpython

// Windows only

#pragma comment(lib, "Gdi32.lib")

#include <math.h>

#include "dpi_aware.h"

#include "include/wrapper/cef_closure_task.h"

#include "include/base/cef_bind.h"

#include "include/base/cef_logging.h"

const int DEFAULT_DPIX = 96;

bool IsProcessDpiAware() {

typedef BOOL(WINAPI *IsProcessDPIAwarePtr)(VOID);

IsProcessDPIAwarePtr is_process_dpi_aware_func =

reinterpret_cast<IsProcessDPIAwarePtr>(

GetProcAddress(GetModuleHandleA("user32.dll"),

"IsProcessDPIAware"));

BOOL is_aware = FALSE;

if (is_process_dpi_aware_func) {

is_aware = is_process_dpi_aware_func();

if (is_aware == TRUE) {

return true;

}

// GetProcessDpiAwareness is available only on Win8. So it

// should be called only as a back-up plan after IsProcessDPIAware

// was called. Also if IsProcessDPIAware returned false,

// then GetProcessDpiAwareness is called as well.

if (GetProcessDpiAwareness() != PROCESS_DPI_UNAWARE) {

return true;

}

return false;

}

PROCESS_DPI_AWARENESS GetProcessDpiAwareness() {

// Win8.1 supports monitor-specific DPI scaling, so it is

// recommended to use GetProcessDPIAwareness instead of the

// deprecated IsProcessDPIAware.

typedef HRESULT(WINAPI *GetProcessDpiAwarenessPtr)

(HANDLE,PROCESS_DPI_AWARENESS*);

GetProcessDpiAwarenessPtr get_process_dpi_awareness_func =

reinterpret_cast<GetProcessDpiAwarenessPtr>(

GetProcAddress(GetModuleHandleA("user32.dll"),

"GetProcessDpiAwarenessInternal"));

if (get_process_dpi_awareness_func) {

HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, false,

GetCurrentProcessId());

PROCESS_DPI_AWARENESS result;

HRESULT hr = get_process_dpi_awareness_func(hProcess, &result);

if (SUCCEEDED(hr)) {

return result;

}

// Possible failures include E_INVALIDARG or E_ACCESSDENIED.

LOG(INFO) << "[Browser process] GetProcessDpiAwareness():"

" hr=" << hr;

}

return PROCESS_DPI_UNAWARE;

}

void SetProcessDpiAware() {

// Win8.1 supports monitor-specific DPI scaling, so it is

// recommended to use SetProcessDPIAwareness instead of the

// deprecated SetProcessDPIAware. SetProcessDpiAwareness is

// only available on Win8. So as a back-up plan SetProcessDPIAware

// is called.

// If DPI aware manifest was embedded in executable, or

// "Disable display scaling on high DPI settings" was checked

// on the executable properties (Compatibility tab), then

// DPI awareness is already set.

What if GetProcessDpiAwareness returned

PROCESS_PER_MONITOR_DPI_AWARE? The code below sets awareness

to PROCESS_SYSTEM_DPI_AWARE, so it should be called either way.

--OFF:

if (IsProcessDpiAware()) {

return;

}

typedef BOOL(WINAPI *SetProcessDpiAwarenessPtr)(PROCESS_DPI_AWARENESS);

SetProcessDpiAwarenessPtr set_process_dpi_awareness_func =

reinterpret_cast<SetProcessDpiAwarenessPtr>(

GetProcAddress(GetModuleHandleA("user32.dll"),

"SetProcessDpiAwarenessInternal"));

if (set_process_dpi_awareness_func) {

LOG(INFO) << "[Browser process] SetProcessDpiAware():"

" calling user32.dll SetProcessDpiAwareness";

HRESULT hr = set_process_dpi_awareness_func(PROCESS_SYSTEM_DPI_AWARE);

if (SUCCEEDED(hr)) {

LOG(INFO) << "[Browser process]: SetBrowserDpiAware():"

" SetProcessDpiAwareness succeeded";

return;

} else if (hr == E_ACCESSDENIED) {

LOG(ERROR) << "[Browser process] SetBrowserDpiAware():"

" SetProcessDpiAwareness failed:"

" The DPI awareness is already set, either by calling"

" this API previously or through the application"

" (.exe) manifest.";

// Do not return here, let's try to call SetProcessDPIAware.

} else {

LOG(ERROR) << "[Browser process] SetBrowserDpiAware():"

" SetProcessDpiAwareness failed";

// Do not return here, let's try to call SetProcessDPIAware.

}

// SetProcessDpiAwareness not found in user32.dll or the call failed.

typedef BOOL(WINAPI *SetProcessDPIAwarePtr)(VOID);

SetProcessDPIAwarePtr set_process_dpi_aware_func =

reinterpret_cast<SetProcessDPIAwarePtr>(

GetProcAddress(GetModuleHandleA("user32.dll"),

"SetProcessDPIAware"));

if (set_process_dpi_aware_func) {

// If cefpython.Initialize() wasn't yet called, then

// this log message won't be written, as g_debug is

// is set during CEF initialization.

LOG(INFO) << "[Browser process] SetProcessDpiAware():"

" calling user32.dll SetProcessDPIAware";

set_process_dpi_aware_func();

}

void GetSystemDpi(int* dpix, int* dpiy) {

// Win7 DPI (Control Panel > Appearance and Personalization > Display):

// text size Larger 150% => dpix/dpiy 144

// text size Medium 125% => dpix/dpiy 120

// text size Smaller 100% => dpix/dpiy 96

// DPI settings should not be cached. When SetProcessDpiAware

// is not yet called, then OS returns 96 DPI, even though it

// is set to 144 DPI. After DPI Awareness is enabled for the

// running process it will return the correct 144 DPI.

HDC hdc = GetDC(HWND_DESKTOP);

*dpix = GetDeviceCaps(hdc, LOGPIXELSX);

*dpiy = GetDeviceCaps(hdc, LOGPIXELSY);

ReleaseDC(HWND_DESKTOP, hdc);

}

void GetDpiAwareWindowSize(int* width, int* height) {

int dpix = 0;

int dpiy = 0;

GetSystemDpi(&dpix, &dpiy);

double newZoomLevel = 0.0;

// 1. Using only "dpix" value to calculate zoom level. All

// modern displays have equal horizontal and vertical resolution.

// 2. Calculation for DPI < 96 is not yet supported (newZoomLevel<0.0).

newZoomLevel = (dpix - DEFAULT_DPIX) / 24;

if (newZoomLevel > 0.0) {

*width = *width + (int)ceil(newZoomLevel * 0.25 * (*width));

*height = *height + (int)ceil(newZoomLevel * 0.25 * (*height));

LOG(INFO) << "[Browser process] GetDpiAwareWindowSize():"

" enlarged by " << ceil(newZoomLevel * 0.25 * 100) << "%"

" new size = " << *width << "/" << *height;

}

void SetBrowserDpiSettings(CefRefPtr<CefBrowser> cefBrowser,

CefString autoZooming) {

// Setting zoom level immediately after browser was created

// won't work. We need to wait a moment before we can set it.

REQUIRE_UI_THREAD();

double oldZoomLevel = cefBrowser->GetHost()->GetZoomLevel();

double newZoomLevel = 0.0;

int dpix = 0;

int dpiy = 0;

GetSystemDpi(&dpix, &dpiy);

if (autoZooming.ToString() == "system_dpi") {

// Using only "dpix" value to calculate zoom level. All

// modern displays have equal horizontal/vertical resolution.

// Examples:

// dpix=96 zoom=0.0

// dpix=120 zoom=1.0

// dpix=144 zoom=2.0

// dpix=72 zoom=-1.0

newZoomLevel = (dpix - DEFAULT_DPIX) / 24;

} else {

// When atof() fails converting string to double, then

// 0.0 is returned.

newZoomLevel = atof(autoZooming.ToString().c_str());

}

if (oldZoomLevel != newZoomLevel) {

cefBrowser->GetHost()->SetZoomLevel(newZoomLevel);

if (cefBrowser->GetHost()->GetZoomLevel() != oldZoomLevel) {

// OK succes.

LOG(INFO) << "[Browser process] SetBrowserDpiSettings():"

" DPI=" << dpix << ""

" zoom=" << cefBrowser->GetHost()->GetZoomLevel();

}

} else {

// This code block running can also be a result of executing

// SetZoomLevel(), as GetZoomLevel() didn't return the new

// value that was set. Documentation says that if SetZoomLevel

// is called on the UI thread, then GetZoomLevel should

// immediately return the same value that was set. Unfortunately

// this seems not to be true.

static bool already_logged = false;

if (!already_logged) {

already_logged = true;

// OK success.

LOG(INFO) << "[Browser process] SetBrowserDpiSettings():"

" DPI=" << dpix << ""

" zoom=" << cefBrowser->GetHost()->GetZoomLevel();

}

// We need to check zooming constantly, during loading of pages.

// If we set zooming to 2.0 for localhost/ and then it navigates

// to google.com, then the zomming is back at 0.0 and needs to

// be set again.

CefPostDelayedTask(

TID_UI,

CefCreateClosureTask(

base::Bind(&SetBrowserDpiSettings,

cefBrowser, autoZooming)

);

}

cefpython/src/client_handler/dpi_aware.cpp at cefpython57 · pythonthings/cefpython · GitHub

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