Question

我可以使用function getVisiblePixelsBoundingBox(canvas) { const context = canvas.getContext("2d"); const imageData = context.getImageData(0, 0, canvas.width, canvas.height).data; let minX = Infinity, minY = Infinity, maxX = -Infinity, maxY = -Infinity; for (let y = 0; y < canvas.height; y++) { for (let x = 0; x < canvas.width; x++) { const alpha = imageData[(y * canvas.width + x) * 4 + 3]; if (alpha > 0) { minX = Math.min(minX, x); minY = Math.min(minY, y); maxX = Math.max(maxX, x); maxY = Math.max(maxY, y); } } } return { left: minX, top: minY, width: maxX - minX, height: maxY - minY }; } // you will need to create a new canvas var canvas = document.createElement("canvas"), context = canvas.getContext("2d"); // and set the width and height the same as the canvas you want to draw the text // here I'm just adding some values for the example: canvas.width = 600; canvas.height = 400; // now I'm going to draw some text on it context.font = "120px serif"; context.fillText("Lipsum", 100, 200); let boundingBox = getVisiblePixelsBoundingBox(canvas); // now this is not needed in your case, but want to see the canvas and // I will draw a rectangle around the bounding box to see how it works: document.body.appendChild(canvas); context.strokeStyle = "red"; context.strokeRect(boundingBox.left, boundingBox.top, boundingBox.width, boundingBox.height);和.pro文件创建项目文件.cpp，此GitHub demo文件包含.h个文件，但没有CMakeLists.txt,MainWindow.cpp MainWindow.h,MainWindow.uimain.cpp } file如何制作.pro

Answer 1

为了执行此代码，第一步是生成.pro，它会打开一个终端并执行：

qmake -project

使用包含它的文件夹名称生成.pro文件，该文件将包含类似于以下内容：

<强> sizegripitem-master.pro

######################################################################
# Automatically generated by qmake (3.1) Tue Oct 24 12:36:31 2017
######################################################################

TEMPLATE = app
TARGET = sizegripitem-master
INCLUDEPATH += .

# The following define makes your compiler warn you if you use any
# feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

# Input
HEADERS += SizeGripItem.h demo/MainWindow.h
FORMS += demo/MainWindow.ui
SOURCES += SizeGripItem.cpp demo/main.cpp demo/MainWindow.cpp

之后我们必须指出模块，因为我看到类只需要模块core，gui和widget，我们添加以下内容：

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

您应该做的另一件事是更新一行代码以与Qt5兼容，在main.cpp文件中更改：

#include <QtGui/QApplication>

为：

#include <QApplication>

我可以使用.cpp和.h文件制作.pro文件

1 个答案: