从像素缓冲区创建HBITMAP然后渲染
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好吧,所以我真的开始使用WinAPI绘制位图图像。所以,如果我的代码是绝对垃圾,我道歉。无论如何,我该怎么做呢?基本上,我想使用像这样的HBITMAP
从一个简单的unsigned char
像素缓冲区创建一个CreateBitmap()
对象...
HBITMAP hbm = CreateBitmap(width, height, 1, 24, buffer);
(显然这是每像素3个字节)
这似乎工作正常,直到我尝试渲染它。现在,我只是想保持简单,并在屏幕上绘制一个100×100的黑色像素正方形,但没有任何显示。如果有人能指出我残暴的代码中的错误,我将不胜感激。
这是我的设置(我知道很多事情都可以改进我现在想尽可能简约,实际上有些东西出现在屏幕上):
HBITMAP hbm = NULL;
void window_init(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
static unsigned char buffer[30000] = {0};
hbm = CreateBitmap(100, 100, 1, 24, buffer);
}
void window_draw(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
HDC hdc = BeginPaint(hwnd, &ps);
HDC hdcMem = CreateCompatibleDC(hdc);
HBITMAP hbmOld = SelectObject(hdcMem, hbm);
BitBlt(hdc, 100, 100, 100, 100, hdcMem, 0, 0, SRCCOPY);
SelectObject(hdcMem, hbmOld);
DeleteDC(hdcMem);
EndPaint(hwnd, &ps);
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
switch (msg) {
case WM_CREATE: window_init(hwnd, msg, wParam, lParam); break;
case WM_PAINT: window_draw(hwnd, msg, wParam, lParam); break;
case WM_CLOSE: DestroyWindow(hwnd); break;
case WM_DESTROY: PostQuitMessage(0); break;
default: return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
这是我的整个代码,以防你要复制它...
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
typedef struct {
const char *wc_name;
const char *title;
unsigned int width;
unsigned int height;
} Window;
static HBITMAP hbmp = NULL;
static PAINTSTRUCT ps;
void window_create(Window *window, const char *wc_name, const char *title, unsigned int width, unsigned int height) {
window->wc_name = wc_name;
window->title = title;
window->width = width;
window->height = height;
}
void window_init(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
static unsigned char buffer[30000] = {0};
hbmp = CreateBitmap(100, 100, 1, 24, buffer);
}
void window_draw(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
HDC hdc = BeginPaint(hwnd, &ps);
HDC hdcMem = CreateCompatibleDC(hdc);
HBITMAP hbmOld = SelectObject(hdcMem, hbmp);
BitBlt(hdc, 100, 100, 100, 100, hdcMem, 0, 0, SRCCOPY);
SelectObject(hdcMem, hbmOld);
DeleteDC(hdcMem);;
EndPaint(hwnd, &ps);
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
switch (msg) {
case WM_CREATE: window_init(hwnd, msg, wParam, lParam); break;
case WM_PAINT: window_draw(hwnd, msg, wParam, lParam); break;
case WM_CLOSE: DestroyWindow(hwnd); break;
case WM_DESTROY: PostQuitMessage(0); break;
default: return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
Window window;
window_create(&window, "Parent Window", "My Window", 1000, 1000 / 16 * 9);
WNDCLASSEX wc = {0};
MSG msg = {0};
HWND hwnd = NULL;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WndProc;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
wc.lpszClassName = window.wc_name;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if (!RegisterClassEx(&wc)) {
MessageBox(NULL, "Failed to register application window!", "WC Registration Error!", MB_ICONEXCLAMATION | MB_OK);
return -1;
}
hwnd = CreateWindowEx(
0, window.wc_name, window.title,
WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
window.width, window.height, NULL, NULL, hInstance, NULL
);
if (!hwnd) {
MessageBox(NULL, "Failed to launch application window!", "HWND Creation Error!", MB_ICONEXCLAMATION | MB_OK);
return -1;
}
ShowWindow(hwnd, SW_MAXIMIZE);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0) > 0) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
答案
与CreateBitmap
不同,CreateDIBSection
生成设备相关位图的句柄,如果成功,保证与设备上下文一起创建与设备无关的位图,并允许您访问位图中的实际位,这与CreateCompatibleBitmap
不同。
如何使用CreateDIBSection
:
HDC hdc = GetDC(hwnd);
BITMAPINFO bi = { 0 };
static BYTE *bits = NULL;
static unsigned char buffer[30000] = { 0 };
bi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bi.bmiHeader.biWidth = 100;
bi.bmiHeader.biHeight = 100;
bi.bmiHeader.biPlanes = 1;
bi.bmiHeader.biBitCount = 24;
bi.bmiHeader.biCompression = BI_RGB;
hbmp = CreateDIBSection(hdc, &bi, DIB_RGB_COLORS, (void**)&bits, NULL, 0);
CopyMemory(bits, buffer, 30000); // Can be replaced with arbitrary RGB value population
ReleaseDC(hwnd, hdc);
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