win32-custom-window/win32_custom_window.c

870 lines
28 KiB
C

/*
** Win32 Custom Window Example Program
** v1.3.1 - Jan 19th 2024
** by Allen Webster allenw@mr4th.com
**
** public domain example program
** NO WARRANTY IMPLIED; USE AT YOUR OWN RISK
**
**
** Tested on: Windows 7 aero, Windows 7 classic, Windows 10
**
**
** This is an example only, it is designed for:
** Easy copy-pasting the main components
** Learn how and why it works
** Build, step through, modify, experiment
**
** This example is not designed for use as a library/engine/framework etc.
**
**
** This example *does show* how to create a win32 window where the client area
** covers the whole area of the window and is an axis aligned rectangle. It shows
** how to maintain normal window resizing, moving, and positioning shortcuts like
** WinKey + Arrows for such a window. And it shows how to handle widgets that are
** placed inside the caption area of the window.
**
** This example *does not show* non-rectangular windows or transparency. It does
** not show a fully abstracted win32 main loop for an application or game. It does
** not show graphics context setup.
**
**
** Most important points:
** CustomBorderWindowProc
** CreateWindowW
**
**
** Required windows libraries:
** User32.lib UxTheme.lib Dwmapi.lib
** Pragmas versions:
** #pragma comment(lib, "User32.lib")
** #pragma comment(lib, "UxTheme.lib")
** #pragma comment(lib, "Dwmapi.lib")
**
** Libraries only for rendering, not required:
** Gdi32.lib
**
**
** Additional contributions from:
** Martins Mozeiko
**
*/
#include <Windows.h>
#include <Windowsx.h>
// only for vsync, not necessary in copies:
#include <dwmapi.h>
// only for logging, not necessary in copies:
#include <stdio.h>
////////////////////////////////
// For simplicity this example statically defines the border and caption width.
// These determine the size of the area where resizing and moving the window
// is possible. There is no reason in principle why these have to be statically
// determined or why these would be the only options in setting up the border
// shape.
int caption_width = 30;
int border_width = 10;
////////////////////////////////
// These fascilitate communication between the message handling loop and the
// update function.
// The application has a way to report widgets that overlap the caption of the
// window so that clicking them will not move the window. A detailed discussion
// of this problem can be found at WM_NCHITTEST.
// With 100% control of how the border looks it is nice to be able to determine
// if the window is active so that it's border can respond with some kind of
// visual que to being inactive.
// Besides those points the details of this aren't specific to a custom window
// they are just mimicking a simple system layer <-> application layer interface.
int WindowIsActive(void);
void StopRunning(void);
void Minimize(HWND hwnd);
void ToggleMaximize(HWND hwnd);
void EmbeddedWidgetRect(RECT rect);
typedef enum{
InputEventKind_MouseLeftPress,
InputEventKind_MouseLeftRelease,
} Input_Event_Kind;
typedef struct Input_Event Input_Event;
struct Input_Event{
Input_Event *next;
Input_Event_Kind kind;
};
typedef struct Input Input;
struct Input{
Input_Event *first_event;
Input_Event *last_event;
int mouse_x;
int mouse_y;
int left;
};
void UpdateAndRender(HWND hwnd, Input *input);
////////////////////////////////
// A handy helper for this example
int
HitTest(int x, int y, RECT rect){
return((rect.left <= x && x < rect.right) && (rect.top <= y && y < rect.bottom));
}
////////////////////////////////
// Implementation for the pseudo system layer.
int keep_running = 0;
int window_is_active = 1;
int minimize_at_end_of_update = 0;
int toggle_maximize_at_end_of_update = 0;
int
WindowIsActive(void){
return(window_is_active);
}
void
StopRunning(void){
keep_running = 0;
}
void
Minimize(HWND hwnd){
minimize_at_end_of_update = 1;
}
void
ToggleMaximize(HWND hwnd){
toggle_maximize_at_end_of_update = 1;
}
#define MAX_EMBEDDED_WIDGETS 128
int embedded_widget_count = 0;
RECT embedded_widget_rect[MAX_EMBEDDED_WIDGETS];
void
EmbeddedWidgetRect(RECT rect){
if (embedded_widget_count < MAX_EMBEDDED_WIDGETS){
embedded_widget_rect[embedded_widget_count] = rect;
embedded_widget_count += 1;
}
}
////////////////////////////////
BOOL composition_enabled;
#define MAX_INPUT_EVENT_COUNT 128
int input_event_cursor = 0;
Input_Event input_event_memory[MAX_INPUT_EVENT_COUNT];
Input input;
Input_Event*
PushEvent(void){
Input_Event *result = 0;
if (input_event_cursor < MAX_INPUT_EVENT_COUNT){
result = &input_event_memory[input_event_cursor];
input_event_cursor += 1;
if (input.first_event == 0){
input.first_event = result;
}
if (input.last_event != 0){
input.last_event->next = result;
}
input.last_event = result;
}
return(result);
}
// The WindowProc callback does most of the work for a custom boredred window.
// The messages that start with "WM_NC" deal with processing the non-client
// area of the window. The main goal is to leave window moving and resizing
// up to the OS while taking control of the rendering and border widgets.
LRESULT
CustomBorderWindowProc(HWND hwnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam){
LRESULT result = 0;
switch (uMsg){
// The WM_NCCALCSIZE is used to establish the mapping from the window's
// non-client area to the client area. The non-client area is passed to
// this code through a pointer in lParam that points to the RECT type.
// Then this code indicates the mapping to a client area by modifying
// that RECT.
// The WM_NCCALCSIZE documentation mentions a circumstance where wParam
// is true and another where wParam is false, and the possibility that
// lParam points to the type NCCALCSIZE_PARAMS. It turns out that the
// first member of NCCALCSIZE_PARAMS is a RECT, and that if the rest
// of the NCCALCSIZE_PARAMS structure is ignored then this message
// behaves the same way in eitehr case. NCCALCSIZE_PARAMS offers
// additional features that are not not used here.
// The main strategy is to leave the client area the same as the
// non-client area by not modifying the RECT at all. This way the whole
// window will be considered client area and the rendering of the border
// is just the same as rendering anything else inside the window.
// However there is a circumstance when this strategy doesn't work.
// When a window is maximized the OS will automatically allow the
// window's area hang a little outside of the monitor. When a window
// uses the default border this makes it so that the maximized window
// doesn't show it's border. This behavior can't be disabled but
// it is possible nullify the effect by querying how wide the overhang
// area will be and pushing the non-client area in by that amount.
// Pushing in the client area gives the render target for the application
// the correct area, but it still leaves an unrendered artifact hanging
// outside of the window, which is visible for users with multiple
// monitors. Calling DwmExtendFrameIntoClientArea addresses this. Normally
// this call widens the area thw window paints as part of border by
// pushing in the interior of the window frame. In this case where border
// rendering is in application code it just pushes in the area where
// the overhang artifact is visible to the point where it is removed.
case WM_NCCALCSIZE:
{
MARGINS m = { 0, 0, 0, 0 };
RECT* r = (RECT*)lParam;
// A convenient function for checking if a window is maximized.
if (IsZoomed(hwnd)){
int x_push_in = GetSystemMetrics(SM_CXFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
int y_push_in = GetSystemMetrics(SM_CYFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
r->left += x_push_in;
r->top += y_push_in;
r->bottom -= x_push_in;
r->right -= y_push_in;
m.cxLeftWidth = m.cxRightWidth = x_push_in;
m.cyTopHeight = m.cyBottomHeight = y_push_in;
}
if (composition_enabled){
DwmExtendFrameIntoClientArea(hwnd, &m);
}
}break;
// TODO(allen): This message relates to Windows 7 and Vista where the DWM mode
// can change. I need to experiment with it before leaving commentary.
case WM_DWMCOMPOSITIONCHANGED:
{
DwmIsCompositionEnabled(&composition_enabled);
if (composition_enabled){
MARGINS m = { 0, 0, 0, 0 };
if (IsZoomed(hwnd)){
int x_push_in = GetSystemMetrics(SM_CXFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
int y_push_in = GetSystemMetrics(SM_CYFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
m.cxLeftWidth = m.cxRightWidth = x_push_in;
m.cyTopHeight = m.cyBottomHeight = y_push_in;
}
DwmExtendFrameIntoClientArea(hwnd, &m);
}
}break;
// The WM_NCACTIVATE message is sent to a window before the WM_ACTIVATE
// message. When a window uses the default border this message is used
// to repaint the border to indicate the change of status to active or
// inactive. This would paint over the custom window border. This code
// simply overrides that behavior with tracking the window state. It is
// still necessary to return true from this message so that normal window
// activation handling continues and so that the WM_ACTIVATE message is
// still sent.
// The documentation for WM_NCACTIVATE says without explanation:
// "If the window is minimized when this message is received, the
// application should pass the message to the DefWindowProc function"
// This code follows this instruction, but for extra caution passes
// -1 instead of lParam as the docs suggest this will prevent it from
// rendering.
case WM_NCACTIVATE:
{
result = 1;
window_is_active = wParam;
// A convenient function for checking if a window is minimized.
if (IsIconic(hwnd)){
result = DefWindowProcW(hwnd, uMsg, wParam, -1);
}
}break;
// The WM_NCHITTEST message is used to map points on the window to
// a symbol indicating the "behavior" of that point. The possible
// "behaviors" include resizing, moving, clicking close, minimize,
// and maximize buttons, being outside of the window, and being
// inside the client area.
// In some versions of Windows using the behaviors for the various
// buttons causes unwanted rendering for the buttons, so those
// are not used in this custom window border. Luckily there is not
// much difficulty in recreating the buttons.
// There is one tricky problem with handling this message. The problem
// occurs if your custom border embeds any widgets along the area that
// would be considered the "caption" of the window which really means
// the area that can be grabbed to move the window around. For example
// the close, minimize, and maximize buttons are widgets embedded in
// the caption. Generally any widget that overlaps any part of the
// area that would be for moving the window.
//
// When a point is inside an embedded widget this message should return
// HTCLIENT so that normal mouse events are sent to the application layer.
// The problem is that the application is going to be in charge of placing
// those buttons, so there must be a strategy for getting that information
// back to this message which expects an immediate response, not a response
// later on in the frame.
// Some ideas of strategies to consider:
// 1. Just don't have any embedded widgets.
//
// > This works but it does mean you're officially giving up on replacing
// the normal close, minimize, maximize buttons.
// 2. Only allow embedded widgets that immediately move the window when
// clicked so that there is no chance of accidentally moving the
// window when trying to use the widgets.
//
// > This works but is very restricting, and requires buttons that
// respond on mouse down immediately instead of mouse up.
// 3. Pre-define the embedded widget layout and have both the application
// layer and platform layer depend on this pre-defined layout rule.
//
// > This works but it does couple the platform layer to things that could
// have been purely application controlled concepts.
// 4. Have the application layer set a "widget rectangle list" when it
// updates and always use the most recent one
//
// > This works but it is also the most work to set up in the platform
// layer and requires the update function to do new work too.
// Certainly there are more possible strategies, this list is just mean
// to offer a few ideas, mostly to clarify the nature of the problem.
// This example is using strategy 4.
case WM_NCHITTEST:
{
POINT pos;
pos.x = GET_X_LPARAM(lParam);
pos.y = GET_Y_LPARAM(lParam);
// Make sure the point is inside of the window
RECT frame_rect;
GetWindowRect(hwnd, &frame_rect);
if (!HitTest(pos.x, pos.y, frame_rect)){
result = HTNOWHERE;
}
else{
RECT rect;
GetClientRect(hwnd, &rect);
ScreenToClient(hwnd, &pos);
// Check each border
int l = 0;
int r = 0;
int b = 0;
int t = 0;
if (!IsZoomed(hwnd)){
if (rect.left <= pos.x && pos.x < rect.left + border_width){
l = 1;
}
if (rect.right - border_width <= pos.x && pos.x < rect.right){
r = 1;
}
if (rect.bottom - border_width <= pos.y && pos.y < rect.bottom){
b = 1;
}
if (rect.top <= pos.y && pos.y < rect.top + border_width){
t = 1;
}
}
// If the point is in two borders, use the corresponding corner resize.
// If the point is in just one border, use the corresponding side resize.
if (l){
if (t){
result = HTTOPLEFT;
}
else if (b){
result = HTBOTTOMLEFT;
}
else{
result = HTLEFT;
}
}
else if (r){
if (t){
result = HTTOPRIGHT;
}
else if (b){
result = HTBOTTOMRIGHT;
}
else{
result = HTRIGHT;
}
}
else if (t){
result = HTTOP;
}
else if (b){
result = HTBOTTOM;
}
// Here the point must be further inside the window than the resize
// borders, so the final options are the window moving area (caption)
// and the client area.
else{
if (rect.top <= pos.y && pos.y < rect.top + caption_width){
result = HTCAPTION;
// Check the application defined widget areas
for (int i = 0; i < embedded_widget_count; i += 1){
if (HitTest(pos.x, pos.y, embedded_widget_rect[i])){
result = HTCLIENT;
break;
}
}
}
else{
result = HTCLIENT;
}
}
}
}break;
// This is only included to emphasize that there is no reason to handle
// any of these WM_NC* messages. They give the window the opportunity
// to handle mouse events in the non-client area before generating the
// equivalent client area versions. If WM_NCHITTEST returns HTCLIENT
// then the default handling for these is to generate the client area
// version of the message. If WM_NCHITTEST generates one of the symbols,
// HTLEFT, HTTOP, ... HTTOPLEFT ... HTCAPTION, then it determined that
// the OS should provide default handling for a resize or move operation.
// In either case, these should just do their default behavior.
#if 0
case WM_NCLBUTTONDOWN:
case WM_NCLBUTTONUP:
case WM_NCLBUTTONDBLCLK:
case WM_NCMBUTTONDBLCLK:
case WM_NCMBUTTONDOWN:
case WM_NCMBUTTONUP:
case WM_NCMOUSEHOVER:
case WM_NCMOUSELEAVE:
case WM_NCMOUSEMOVE:
case WM_NCRBUTTONDBLCLK:
case WM_NCRBUTTONDOWN:
case WM_NCRBUTTONUP:
case WM_NCXBUTTONDBLCLK:
case WM_NCXBUTTONDOWN:
case WM_NCXBUTTONUP:
{
result = DefWindowProcW(hwnd, uMsg, wParam, lParam);
}break;
#endif
case WM_CLOSE:
{
keep_running = 0;
}break;
case WM_SIZING:
{
InvalidateRect(hwnd, 0, 0);
}break;
// It's always a good idea to do *something* with the WM_PAINT message
// so that your window looks better when resizing, but in this case it's
// especially important. Remember your code creates the border graphics
// now, so if you don't render anything when the window is reszing then
// there will be nothing at all to indicate that the window is changing
// size until the resize finishes.
case WM_PAINT:
{
PAINTSTRUCT ps;
BeginPaint(hwnd, &ps);
embedded_widget_count = 0;
UpdateAndRender(hwnd, 0);
EndPaint(hwnd, &ps);
}break;
case WM_LBUTTONDOWN:
{
Input_Event *event = PushEvent();
if (event != 0){
event->kind = InputEventKind_MouseLeftPress;
}
}break;
case WM_LBUTTONUP:
{
Input_Event *event = PushEvent();
if (event != 0){
event->kind = InputEventKind_MouseLeftRelease;
}
}break;
default:
{
result = DefWindowProcW(hwnd, uMsg, wParam, lParam);
}break;
}
return(result);
}
int
WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nShowCmd){
// With CustomBorderWindowProc done, creating the window is not
// that much more work, and is almost identical to creating a
// default window.
#define WINDOW_CLASS L"MainWindow"
// Nothing about the window class differs from a default window.
WNDCLASSW window_class = {0};
window_class.style = 0;
window_class.lpfnWndProc = CustomBorderWindowProc;
window_class.hInstance = hInstance;
window_class.hCursor = LoadCursorA(0, IDC_ARROW);
window_class.lpszClassName = WINDOW_CLASS;
ATOM atom = RegisterClassW(&window_class);
if (atom == 0){
fprintf(stderr, "RegisterClassW failed\n");
exit(1);
}
// One key aspect is making sure these styles are present:
// WS_SIZEBOX, WS_MAXIMIZEBOX, WS_MINIMIZEBOX, WS_CAPTION, WM_SYSMENU
// Because these styles are needed for making shortcuts and
// default resize and moving behavior work, even when the border
// itself is overriden. These are exactly equivalent to the combined style:
// WS_OVERLAPPEDWINDOW
DWORD style = WS_OVERLAPPEDWINDOW;
HWND hwnd = CreateWindowW(WINDOW_CLASS,
L"Window Name",
style,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
0,
0,
hInstance,
0);
if (hwnd == 0){
fprintf(stderr, "CreateWindowExW failed\n");
exit(1);
}
// The other key aspect is SetWindowTheme. Using SetWindowTheme with single
// spaces effectively disables an theme on the window. Doing this is critical
// for removing special shapes, shading, etc. from the default window on
// any given version of Windows.
SetWindowTheme(hwnd, L" ", L" ");
// A convenient way to get vsync since this example doesn't have a more
// sophistcated graphics context.
if (DwmIsCompositionEnabled(&composition_enabled) != S_OK){
fprintf(stderr, "DwmIsCompositionEnabled failed\n");
composition_enabled = 0;
}
fprintf(stdout, "Has compositor? %s\n", composition_enabled?"Yes":"No");
ShowWindow(hwnd, SW_SHOW);
keep_running = 1;
for (;keep_running;){
input.first_event = 0;
input.last_event = 0;
input_event_cursor = 0;
// Personal preference - I like to put anything that resizes the window
// from my code after the main update so that I can assume that the
// size never changes during the update. This also happens to be a
// convenient way to make sure I immediately redo my layout and render
// after a size change.
MSG msg;
if (minimize_at_end_of_update){
ShowWindow(hwnd, SW_MINIMIZE);
}
else if (toggle_maximize_at_end_of_update){
if (IsZoomed(hwnd)){
ShowWindow(hwnd, SW_RESTORE);
}
else{
ShowWindow(hwnd, SW_MAXIMIZE);
}
}
else{
GetMessage(&msg, 0, 0, 0);
TranslateMessage(&msg);
DispatchMessage(&msg);
}
for (;PeekMessageW(&msg, 0, 0, 0, PM_REMOVE);){
TranslateMessage(&msg);
DispatchMessage(&msg);
}
POINT mpos;
GetCursorPos(&mpos);
ScreenToClient(hwnd, &mpos);
input.mouse_x = mpos.x;
input.mouse_y = mpos.y;
input.left = (GetKeyState(VK_LBUTTON)&(1 << 15));
minimize_at_end_of_update = 0;
toggle_maximize_at_end_of_update = 0;
embedded_widget_count = 0;
UpdateAndRender(hwnd, &input);
// This can be whatever vsync or frame rate limiting method you'd
// like or none at all.
if (composition_enabled){
DwmFlush();
}
else{
Sleep(33);
}
}
return(0);
}
////////////////////////////////
// The implementation of the application tick function which renders the border,
// inside of the window, and embedded widgets, and processes input for both the
// border and the interior through a single input system.
int
HasEvent(Input *input, Input_Event_Kind kind){
int result = 0;
if (input != 0){
Input_Event **ptr_to = &input->first_event;
Input_Event *last = 0;
for (Input_Event *event = input->first_event, *next = 0;
event != 0;
event = next){
next = event->next;
if (event->kind == kind){
result = 1;
*ptr_to = next;
if (event == input->last_event){
input->last_event = last;
}
break;
}
else{
ptr_to = &event->next;
last = event;
}
}
}
return(result);
}
typedef enum{
Widget_None,
Widget_Close,
Widget_Minimize,
Widget_Maximize,
Widget_Slider,
} Widget;
Widget click_started = Widget_None;
int slider_x = 0;
int delta_from_mouse_x = 0;
void
UpdateAndRender(HWND hwnd, Input *input){
RECT window_rect;
GetClientRect(hwnd, &window_rect);
RECT inside_rect;
inside_rect.top = window_rect.top + caption_width;
if (!IsZoomed(hwnd)){
inside_rect.left = window_rect.left + border_width;
inside_rect.right = window_rect.right - border_width;
inside_rect.bottom = window_rect.bottom - border_width;
}
else{
inside_rect.left = window_rect.left;
inside_rect.right = window_rect.right;
inside_rect.bottom = window_rect.bottom;
}
HDC dc = GetDC(hwnd);
{
SelectObject(dc, GetStockObject(DC_PEN));
SelectObject(dc, GetStockObject(DC_BRUSH));
// Window border
{
if (WindowIsActive()){
SetDCPenColor(dc, RGB(255, 200, 0));
SetDCBrushColor(dc, RGB(255, 200, 0));
}
else{
SetDCPenColor(dc, RGB(128, 100, 0));
SetDCBrushColor(dc, RGB(128, 100, 0));
}
Rectangle(dc, window_rect.left, window_rect.top, window_rect.right, inside_rect.top);
Rectangle(dc, window_rect.left, inside_rect.bottom, window_rect.right, window_rect.bottom);
Rectangle(dc, window_rect.left, inside_rect.top, inside_rect.left, inside_rect.bottom);
Rectangle(dc, inside_rect.right, inside_rect.top, window_rect.right, inside_rect.bottom);
}
// Close button
if (window_rect.right > 20){
RECT button;
button.left = window_rect.right - 20;
button.top = window_rect.top + 10;
button.right = window_rect.right - 10;
button.bottom = window_rect.top + 20;
SetDCPenColor(dc, RGB(180, 0, 0));
SetDCBrushColor(dc, RGB(180, 0, 0));
EmbeddedWidgetRect(button);
Rectangle(dc, button.left, button.top, button.right, button.bottom);
if (input != 0 && HitTest(input->mouse_x, input->mouse_y, button)){
if (HasEvent(input, InputEventKind_MouseLeftPress)){
click_started = Widget_Close;
}
if (click_started == Widget_Close && HasEvent(input, InputEventKind_MouseLeftRelease)){
StopRunning();
}
}
}
// Minimize button
if (window_rect.right > 40){
RECT button;
button.left = window_rect.right - 40;
button.top = window_rect.top + 10;
button.right = window_rect.right - 30;
button.bottom = window_rect.top + 20;
SetDCPenColor(dc, RGB(0, 0, 180));
SetDCBrushColor(dc, RGB(0, 0, 180));
EmbeddedWidgetRect(button);
Rectangle(dc, button.left, button.top, button.right, button.bottom);
if (input != 0 && HitTest(input->mouse_x, input->mouse_y, button)){
if (HasEvent(input, InputEventKind_MouseLeftPress)){
click_started = Widget_Minimize;
}
if (click_started == Widget_Minimize && HasEvent(input, InputEventKind_MouseLeftRelease)){
Minimize(hwnd);
}
}
}
// Maximize button
if (window_rect.right > 60){
RECT button;
button.left = window_rect.right - 60;
button.top = window_rect.top + 10;
button.right = window_rect.right - 50;
button.bottom = window_rect.top + 20;
SetDCPenColor(dc, RGB(0, 180, 0));
SetDCBrushColor(dc, RGB(0, 180, 0));
EmbeddedWidgetRect(button);
Rectangle(dc, button.left, button.top, button.right, button.bottom);
if (input != 0 && HitTest(input->mouse_x, input->mouse_y, button)){
if (HasEvent(input, InputEventKind_MouseLeftPress)){
click_started = Widget_Maximize;
}
if (click_started == Widget_Maximize && HasEvent(input, InputEventKind_MouseLeftRelease)){
ToggleMaximize(hwnd);
}
}
}
// Slider
if (window_rect.right > 200){
RECT track;
track.left = window_rect.right - 195;
track.top = window_rect.top + 14;
track.right = window_rect.right - 95;
track.bottom = window_rect.top + 16;
SetDCPenColor(dc, RGB(0, 0, 0));
SetDCBrushColor(dc, RGB(0, 0, 0));
Rectangle(dc, track.left, track.top, track.right, track.bottom);
RECT button;
button.left = window_rect.right - 200 + slider_x;
button.top = window_rect.top + 10;
button.right = window_rect.right - 190 + slider_x;
button.bottom = window_rect.top + 20;
SetDCPenColor(dc, RGB(100, 200, 200));
SetDCBrushColor(dc, RGB(100, 200, 200));
EmbeddedWidgetRect(button);
Rectangle(dc, button.left, button.top, button.right, button.bottom);
if (input != 0){
if (HitTest(input->mouse_x, input->mouse_y, button)){
if (HasEvent(input, InputEventKind_MouseLeftPress)){
click_started = Widget_Slider;
delta_from_mouse_x = slider_x - input->mouse_x;
}
}
if (click_started == Widget_Slider){
slider_x = delta_from_mouse_x + input->mouse_x;
if (slider_x < 0){
slider_x = 0;
}
if (slider_x > 100){
slider_x = 100;
}
}
}
}
if (input != 0 && !input->left){
click_started = Widget_None;
}
// Inside area
{
SetDCPenColor(dc, RGB(127, 127, 127));
SetDCBrushColor(dc, RGB(127, 127, 127));
Rectangle(dc, inside_rect.left, inside_rect.top, inside_rect.right, inside_rect.bottom);
}
}
ReleaseDC(hwnd, dc);
}